







I was wondering what xy means. 
20150930 

From Eric: I was wondering what xy means. My two things I think it means are the two digits of x and y or x times y. thanks for your time,
Eric Answered by Penny Nom. 





Two lorries approaching an intersection 
20150515 

From Nuraini: Two straight roads intersect at the right angles. Lorry A, moving on one of the roads,
Approaches the intersection at 50mi/h and lorry B, moving on the other roads, approaches the intersection at 20mi/h.
At what rate is the distance between the lorry changing when A is 0.4 mile from the intersection and B is 0.3 mile from the intersection? Answered by Penny Nom. 





Two cars approaching an intersection 
20150416 

From Engabu: Car A is traveling west at 50km/h & car B is traveling north at 60km/h. both are headed for the intersection of the two roads. At what rate are the cars approaching each other when car A is 3km & car B is 4km from the intersection? Answered by Penny Nom. 





A train trip 
20150323 

From Ngcebo: A train travels a distance of 720 km at a speed of x km/h. on the return journey, it travels at an average speed of y km/h and completes the whole journey in an hour less. if the speed during the return journey was 10 km/h more, what were the speeds in m/s Answered by Penny Nom. 





Average rate for a return trip 
20150314 

From Michael: Jeffrey drove to a town 25 miles away at an average speed of 50 miles per hour. The return trip along the same route took 20 minutes longer than the trip to town. Determine the average speed in miles per hour for Jeffrey's round trip. Answered by Penny Nom. 





Istanbul to Lagos 
20150303 

From Victor: A plane flies from Istanbul to Lagos at 800km/h and then returns to Istanbul at 900km/h. The return trip takes 1 hour less than the flight to Lagos. What is the distance between Istanbul and Lagos? Answered by Penny Nom. 





Distance, time and rate for three people 
20150215 

From Mubashir: Steven left Town A and walked towards Town B at a speed of 100m/min. At the same time, Jason and Melvin started from Town B and walked towards Town A at a speed of 80m/min and 75m/min respectively. If Steven met Melvin six minutes after passing Jason, find the distance between Town A and Town B. Answered by Penny Nom. 





Speed, distance and time 
20150206 

From Terry: How many seconds would it take to travel 0.18 km at a speed of 130km per hour? Answered by Penny Nom. 





Two cars pass each other going in opposite directions 
20150203 

From Caroline: Two cars pass each other going i opposite directions. One car is going 100 km/h and the other is going 80 km/h. How far apart will the two cars be after driving 45 minutes at these rates of speed? Answered by Penny Nom. 





A train from Vancouver to Whistler 
20150202 

From Tea: Serena and Nina are taking a train from Vancouver to Whistler, a 160km trip. If the average speed is decreased by 16km/hr, the trip will be 1/2 hours longer. What is the average speed of the train?
Thanks :) Answered by Penny Nom. 





A motorbike race 
20150125 

From Pramegh: In a motorbike race of 75 km, the winner completes the race with a lead of 300 meters and 8 seconds before the second rider. Considering the riders ride with an average speed, find the difference between their speeds with which they completed the race.
(Calculate up to 2 decimal places) Answered by Penny Nom. 





Two cars 
20150118 

From taylor: two cars leave the park at the same time, one traveling north at a speed 10 mph faster than the other which is traveling south. after 3 hours the cars are 420 miles apart. find the speed of both cars Answered by Penny Nom. 





Pumping water from a borehole 
20150118 

From patience: An empty tank for storing water from a borehole has a volume of 480 cubic metres. If it is filled by a pump that pumps water at a rate of 16 litres per second, how many hours will it take the pump to fill this tank please show all calculations Answered by Penny Nom. 





196 kilometer in2 hours 
20141229 

From Ekanem: QQ A motorist had planned to reach a place 196km in two hrs exactly. For the first 15km he was able to average only 40km/h. What average speed must he keep up for the rest of the journey if he is to arrive on time. Answered by Penny Nom. 





What is the speed of the boat in still water? 
20141030 

From Adam: The current in a stream moves at a speed of 2 km/h. A boat travels 38 km upstream and 38 km downstream in a total time of 3 hr. What is the speed of the boat in still water? Answered by Penny Nom. 





A man a ship and a wharf 
20140926 

From Ralph: A man om wharf 12 meters above the level of water is pulling a rope tide to a boat at the rate of 2 meters per minute. How fast is the boat approaching the wharf when there are 20 meters of the rope our. (with solution) Answered by Penny Nom. 





Problem solving 
20140908 

From hubert: a car left the house and travelled at an average speed of 60 kph.how many minutes will it take for the car to reach the school which is 8 km away from the house Answered by Penny Nom. 





A car passing a bus 
20140824 

From Athish: the driver of the car is travelling at 36 km/hr and spots a bus 80 m ahead of him after 1 hr the bus is 120 m behind the car what is the speed of the bus Answered by Penny Nom. 





Distance, speed and time 
20140813 

From abdel: Mac walked to a park from the college at 5 km/h. 10 minutes later, Steve started
riding his bike at 15 km/h to the same park to meet Mac. They arrive at the same
time at the park. How far is the park from the college? Answered by Tyler Wood. 





Speed, distance, time 
20140813 

From Aarti: a theif running at 8 km/hr is chased by a policeman whose speed is 10km/hr.if the thief is 100 m ahead the policeman then what will b time required for the policeman to catch the thief? Answered by Tyler Wood. 





What is the speed of the buses? 
20140518 

From musliu: Two buses leave a bus station and travel in opposite direction from that same starting point.if the speed of one is twice the speed of the other and they are 240km apart at the end of 1h, what is the speed of the buses? Answered by Penny Nom. 





Travelling upstream and downstream 
20140512 

From Mohanad: Howie Sorkin can travel 8 miles upstream in the same time it takes him to go 12 miles downstream. His boat goes 15 mph in still water. What is the rate of the current? Answered by Penny Nom. 





2 cars driving towards each other 
20140427 

From Joakim: 2 cars driving towards eachother , the distance between them is 162km. they meet after 2 hours. car A is driving with 4/5 of car B´s speed. what is the speed of each car... Answered by Penny Nom. 





What time was it when joe's brother passed him? 
20140425 

From Nathan: joe left home in his bike at 10:00 am, traveling 21 km/h. At noon, his brother set out after him on his motorcycle, following the same route. if the motorcycle traveled at 63 km/h, what time was it when joe's brother passed him? Answered by Penny Nom. 





A speed word problem 
20140224 

From kiss: Hank bicycles 5 km/h slower than Kelly. In the time that it takes Hank to bicycle 42 km, Kelly can bicycle 57 km. How fast does each bicyclist travel? Answered by Penny Nom. 





How many cubic centimeters are in a cubic meter? 
20140211 

From merylin: How many cubic centimeters are in a cubic meter? Use a sketch to explain your reasoning. Answered by Penny Nom. 





Two bicyclists traveled in opposite directions 
20140207 

From Susan: Two bicyclists traveled in opposite directions, one at a rate of 8 km/hour and the other at a rate of 7 km per hour. In how many hours were they 45 km apart? Answered by Penny Nom. 





Walking up and down a hill 
20140206 

From flo: michelle walks 4 km to the top of a hill at 3 km/h then immediately walks back down at an average speed of 5 km/h what is her average speed for the 8km walk Answered by Penny Nom. 





On what day of the week was July 4, 1904? 
20140111 

From Madi: Hi guys,
I have a question. July 4, 1903, was a Tuesday. On what day of the
week was July 4, 1904? If you could give me an equation that would
work for any question like this, that would be GREAT!
Your fellow math scholar (in training),
Madi Answered by Penny Nom. 





Two tuna boats 
20140109 

From amanda: Two tuna boats start from the same port at the same time, but they head in opposite directions. The faster boat travels 10 knots per hour faster than the slower boat. At the end of 8 hours, they were 272 nautical miles had each boat traveled by the end of the 8 hour period? Answered by Penny Nom. 





One train overtaking another 
20131111 

From kiran: two trains of equal length are running in parallel tracks in the same direction with the speed of 60km/hr and 90km/hr respectively the latter completely crosses the former in 30 seconds the length of each train is in mtr Answered by Penny Nom. 





The average time per mile for a marathoner 
20131104 

From Peter: a runner ran a 26.2 mile marathon in 2hours 8minutes and 24secounds. the question is, what was his average time for each mile that he ran? Answered by Penny Nom. 





What is the original speed? 
20130810 

From MJ: If a truck increases its average speed by 10 km/h it can cover 60 km at the original speed in the same time that it can cover 80 km at the faster speed. What is the original speed? Answered by Penny Nom. 





Diego and his dog 
20130709 

From William: john went hunting and walked at a speed of 4 km/h. one hour later, Diego and his dog went to meet john with a speed of 6 km/h and the dog was running between john and diego until they meet up with a speed of 18 km/h. After Diego meets john, how much distance did the dog run? Answered by Penny Nom. 





If 4 cooks can bake 8 pies in 6 hours????? 
20130318 

From Kenneth: Hello:
I want to determine which quantities are directly and inversely proportional in order to determine the answer for the following:.
If 4 cooks can bake 8 pies in 6 hours, 2 cooks can bake how many pies in 4 hours?
Answer: 2 2/3 pies
Can someone fully explain what I need to know in order to determine what is directly and inversely proportional in the example above?
I thank you for your reply. Answered by Robert Dawson. 





6 miles in 28 minutes what's my average speed? 
20130305 

From lynda: 6 miles in 28 minutes what's my average speed? Answered by Penny Nom. 





An electron in a TV tube 
20130215 

From anu: an electron in a TV tube is beamed horizontally at a speed of (50^6) m/sec. towards the face of a tube 40 cm away
about how far will the electron drop before it hits? no information has been provided of initial height from where it is beamed. Answered by Robert Dawson. 





A journey of two parts 
20130206 

From Natalie: Mr Lim drove at 70 km per hour for 1 hour and 30 minutes. He then drove another 55 km. if his average speed for the whole journey was 80km per hour, what was his speed for the 55 km journey? Answered by Penny Nom. 





How fast are we approaching each other? 
20130111 

From Heather: If I am skating at 7 mph, and a car drives towards me at 15 mph, how fast are we approaching each other? Answered by Penny Nom. 





Two swimmers 
20121022 

From Emily: Two swimmers start from opposite sides of the pool. Each swimmer swims the length of the pool and back at a constant rate. They pass each other for the first time 40 feet from one side of the pool and for the second time 45 feet from the other side of the pool. What is the length of the pool? Answered by Penny Nom. 





A plane travelling with the wind and against the wind 
20120803 

From Gwen: The time of a plane trip of 450 miles, with the wind is 3/5 the time of the return trip against the wind. If the plane travels 120 mph in still air, what is the wind speed? Answered by Penny Nom. 





A cyclist a jogger and a fly 
20120604 

From Emd: A cyclist & a jogger are 20 miles apart.
Cyclist goes 20 mph & jogger 7mph towards each other.
A fly starts on nose of cyclist & flies at 20 mph from cyclist to jogger &
back & forth until they meet.
How far has the fly travelled? Answered by Penny Nom. 





Romeo and Juliet live 40 miles apart 
20120518 

From Abigaíl: Romeo and Juliet live 40 miles apart. Romeo jogs 8mph, while Juliet “fast walks” at 4mph. They leave their houses at the same time and journey toward each other.
a) How many hours after they start will they meet?
b) Approximately how many miles from Romeo’s house is their meeting point? Answered by Penny Nom. 





Math, time and rate 
20120518 

From Abigaíl: Romeo and Juliet live 40 miles apart. Romeo jogs 8mph, while Juliet “fast walks” at 4mph. They leave their houses at the same time and journey toward each other.
a) How many hours after they start will they meet?
b) Approximately how many miles from Romeo’s house is their meeting point? Answered by Penny Nom. 





Cycling and running 
20120507 

From liz: a biathlete travels 20 miles in 2.25 hours. She cycles part of the way at 12 mph and runs the rest at 5 mph. How far did she run? Answered by Penny Nom. 





Two cars approach a rightangled intersection 
20120410 

From Michael: Two cars approach a rightangled intersection, one traveling south a 40km/h and the other west at 70km/h.
When the faster car is 4km from the intersection and the other case if 3km from the intersection,
how fast is the distance between the car cars changing? Answered by Penny Nom. 





How long will it take lee to catch up with jodie? 
20120321 

From kirsten: for example, if jodie is on the bus travelling at 10 m.p.h and lee is walking at 4 m.p.h how long will it take lee to catch up with jodie?? what is this mathematical name for this Answered by Harley Weston. 





Margie threw a ball 
20120216 

From mary: at 9:45 Margie threw a ball upwards while standing on a platform 35ft above the ground. The height after t seconds follows the equation:
h(t)= 0.6t^2 +72t+35
a) what will be the maximum height of the ball?
b)how long will it take the ball reach its maximum height?? Answered by Harley Weston. 





Jack and Kate set off in their cars ... 
20120213 

From akiri: Jack and Kate set off in their cars from the same point to travel the same journey. Jack has a start of eight minutes before Katie sets off. If Jack travels at 50mph and Katie travels at 75mph, how many miles will be travelled when the two cars are level? Answered by Penny Nom. 





There is a police officer in pursuit of suspect 
20120201 

From Jay: There is a police officer in pursuit of suspect. They suspect is driving on a straight road traveling at 79 mph, the officer is 233 yds away, traveling at 92 mph, the suspects car 5 ft long and the officers car is 5.3 ft long, how long will it take to have the front of the officers car, equal to the front of the suspects car down to the tenth of a second. Answered by Harley Weston. 





Two cars in a race 
20120130 

From Christine: In a car race, the speed of one car is 120kph and the other car is 105 kph. If the faster car finished the race 20 mins before the slower one, what was the distance of the race? Thanks for the answer and the previous answer to my question. Answered by Penny Nom. 





Brian on his bike 
20120116 

From tiffany: Brian rides his bike 0.29 miles per minute. If it takes him 22 minutes to ride his bike to his friend's house, how far away does his friend live? Answered by Penny Nom. 





Running 5 km 
20120112 

From Fayeann: What amount of time will it take a person running 7 m/s to travel a distance of 5 km? Answered by Penny Nom. 





Two trains passing each other 
20111207 

From Tamkeen: two trains 245m and 315m long are travelling toward each other at 90km/h and 54km/h respectively on parallel lines . how long do the train take to pass one another train the time they meet each other? Answered by Penny Nom. 





Uniform acceleration 
20111206 

From Android: At a certain instant, two cars A and B are 2000 ft apart. At this instant, car A is traveling at 15 miles/hr. and accelerating at 3 ft/s^2 while B is moving towards A at 30 miles/hr. and an acceleration of 2 ft/s^2.
Find the ff:
a.) The possible time of their collusion in minutes.
b.) The distance in ft. each has traveled before collusion. Answered by Penny Nom. 





Two boats 
20111130 

From Shayan: A boat is traveling 20 miles per hour when it passes a lighthouse.
another boat is traveling at 15 miles per hour when it passes a point.
the lighthouse and the point are 175 miles apart.
when will the boats pass each other? Answered by Penny Nom. 





The average speed for the whole journey 
20111030 

From Shahzad: a train travels 68 Km at an average speed of 51Km/h. It then travels another 20Km at an average speed of 40Km/h before reaching its destination. Calculate the average speed for the whole journey? Answered by Penny Nom. 





What is the speed of the boat in still water? 
20111007 

From Hannah: The speed of a stream is 3 mph. A boat travels 10 miles upstream in the same time it takes to travel 16 miles downstream. What is the speed of the boat in still water Answered by Penny Nom. 





Chuong and Hassan drive to work 
20111004 

From Dilshad: Chuong and Hassan both drive 40 km from home to work each day. One day Chuong said to Hasssan, "If you drive home at your usual speed, I will average 40 kmph faster than you and arrive home in 20 minutes less time." Find Hassan's speed. Answered by Penny Nom. 





The dimension of the box in centimetres 
20110827 

From Eliza: Find the dimension of the box in centimetres. Then find its volume in cubic centimeters.
The box is 0.7m (l) 0.4 (h) 0.2 (w) Answered by Penny Nom. 





Driving to meet Mary 
20110824 

From Denise: mary leaves St Paul traveling 2000 miles @ 55 MPH; John leaves LA traveling 2000 miles @ 45 MPH how many miles will John had traveled to meet mary? Answered by Penny Nom. 





Achilles and a turtle 
20110701 

From Jean: Achilles and a turtle are having a race. The turtle starts 45m ahead of Achilles and Achilles is twice as fast as the turtle. If turtle runs at 1m/s,how far would the turtle have run before he is outrun by Achilles? Answered by Penny Nom. 





Two trains 
20110607 

From Lynn: If the 1st train goes 60 mph and the 2nd train leaves 10 minutes later =
at a speed of 70 mph, how long does it take to catch up with the 1st =
train. Answered by Penny Nom. 





How many meters long should the race be? 
20110526 

From Lee: Nathan can walk at a rate of two meters per second while David can
easily go threeandahalf meters per second. David offers Nathan
a 45 meter head start. How many meters long should the race be in
order for Nathan to win by a nose Answered by Penny Nom. 





Two ships 
20110405 

From Gevork: Ship A is sailing due south at 16 mph. At the same time, a second ship B, 32 miles south of A, is sailing due east at 12 mph.
(a) at what rate are they approaching or separating at the end of one hour?
(b) At what rate are they approaching or separating at the end of two hours?
(c) When do they cease to approach each other and how far apart are they at that instant. Answered by Penny Nom. 





Converting millimeters to centimeters 
20110404 

From Pat: I need to convert 67 mm to centimeters how do I do this? Answered by Penny Nom. 





Two boats 
20110329 

From Mamie: Two speed boats leave the port of San Francisco traveling in opposite directions
at the same time.One boat travels 8 knots per hour faster than the other.After
one day's travel they are 1,920 nautical miles apart.What are the speeds of the
two boats. Answered by Penny Nom. 





What is its speed in miles per hour? 
20110106 

From Miriam: An airliner travels 125miles in 15minutes. What is its speed in miles per hour? Answered by Penny Nom. 





80 miles in 40 minutes 
20101208 

From james: i travel 8o miles in 40 minutes. how fast am i going in mph Answered by Penny Nom. 





What is its speed in still air? 
20101128 

From Shelby: An Airplane flies a certain distance in 3 hours going WITH a 40km/hr wind. It travels the same distance in 5 hours when going against the wind. What is it's speed and how long would it take to travel the same distance in still air? Distance = speed x time Answered by Penny Nom. 





Hours minutes and seconds 
20101126 

From beket: I need to turn 1.486588292 into real time hours minutes and seconds. I keep getting multiple answers. Online conversions give me 1 hour 29 minutes and either 11 or 12 seconds. On the calculator I get 1 hour 29 minutes and 20 seconds. Can you explain how to turn this decimal into time? Answered by Robert Dawson and Penny Nom. 





How long will you and your friend be able to talk? 
20101123 

From beket: you and your friend leave your home town at the same time your friend travels by train 45 mph directly east while you travel by train 50 mph going directly south you are talking on cell phone but you plan charges extra if the phones are 100 miles apart. How long will you and your friend be able to talk before the charges increase? Answered by Penny Nom. 





A train passes a car 
20101024 

From Mary: A train, whose speed is 75 mph, takes 3 minutes to pass a car that is going 60 mph in the same direction. How long is the train? Answered by Stephen La Rocque. 





What are the speeds of the boats? 
20101021 

From Adori: Two boats leave the port of San Francisco traveling in opposite directions at the same time. One boat travels 8 knots per hour faster than
the other. After one day's travel they are 1920 nautical miles apart. What are the speeds of the boats? Answered by Penny Nom. 





John and Mary are 200 miles apart 
20101020 

From Sarah: two people, john and mary, are 200 miles apart and leave at the same time to meet.
They are driving toward each other at constant rate on the same straight road.
John is traveling at 45 mph and Mary is traveling at 35 mph.
When they meet, how many miles will they be from john's house? Answered by Penny Nom. 





A commuter airline between two cities 
20101019 

From Adori: An airline runs a commuter between two cities that are 720 miles apart. If the average speed of the planes is increased by 40 miles per hour, the travel time is decreased An airline runs a commuter between two cities that are 720 miles apart. If the average speed of the planes is increased by 40 miles per hour, the travel time is decreased by 12 minutes. What airspeed is required to obtain this decrease in travel time? Answered by Penny Nom. 





Two jets leave denver at 9 am. 
20101015 

From Carl: two jets leave denver at 9 am. One flying east at a speed of 50 km per hour greater than the other which is traveling west. At 11 am the planes are 2500 km apart. Find their speeds. Answered by Stephen La Rocque. 





Electronic cars around a circular track 
20101011 

From Taylor: Cory and Melissa are racing electronic cars around a circular track. They begin at the same time going in the same direction. Cory's car completes a revolution in 35 secs, while Melissa's car completes a revolution in 30 secs. How long will it take them before both cars reach the starting point again simultaneously? Answered by Stephen La Rocque and Penny Nom. 





Two cars 
20100930 

From Amanda: Two cars, 142 miles apart, start moving towards each other at the same
time. One is moving 3 times as fast as the other. If they meet 1.7 hrs
later, find the average speed of the slower car in miles per hour? Answered by Penny Nom. 





40 mph for 6 minutes 
20100920 

From Andy: If i was traveling at 40 mph for 6 minutes, what is my distance in miles? Answered by Penny Nom. 





Three cars 
20100830 

From Anil: 3 cars are moving at speed of 4 kmph,5.5 kmph and 8 kmph in a circular track.The circular track has
a distance of 11 km. What is the time taken for all the 3 cars to meet at the starting point ? Answered by Stephen La Rocque. 





Running 100 km 
20100812 

From thomas: Another athlete runs 8 laps every day on the same 400m running track. How many days will it take him to run a total of 100 km? Answered by Robert Dawson. 





Two cars on a circular track 
20100812 

From david: If two cars starts to drive at point 1 and go in a circle when will they meet?
(one cars speed is faster the other ) all I need is a formula Answered by Tyler Wood. 





How fast is the second car taveling? 
20100726 

From Jeff: A car is traveling 75 mph. It takes 12 miles to overtake a second car that was .5 mile ahead. How fast is the second car taveling? Answered by Stephen La Rocque. 





How much longer will it take to reach Toronto 
20100722 

From Rachelle: We are taking a trip from Ottawa, ON to Toronto, ON. The total trip is 150 kms and will take us 4.5 hours. We have already driven 108 kms and there is still 42 kms left to go. If we are travelling 110 kms/hr, how much longer will it take to reach Toronto? Answered by Penny Nom. 





Pursuing Car 1 
20100713 

From Mark: Car 1 is traveling down the road at 50mph and passes Car 2 is
sitting on the side of the road. Car 2 needs to catch Car 1 one half mile
down the road. How fast must Car 2 drive to catch Car 1 if Car 2
waits 10 seconds before pursuing Car 1? Answered by Robert Dawson. 





Half a mile at 50 mph 
20100713 

From Mark: How long will it take a car to travel 1/2 mile at 50 mph? Answered by Robert Dawson. 





Going to the bike shop 
20100607 

From Omi: Marie rode her bicycle from her home to the bicycle shop in town and then walked back home. If she averaged 6 miles per hour riding and 3 miles per hour walking, how far is it from her home to the bicycle shop if her total travel time was 1 hour? Answered by Penny Nom. 





What is the distance from A to C via B? 
20100524 

From vivianne: The distance from A to B is d km and that from B to C is x km. if a bus maintains an average speed of 50km/hr between A and B and 60km/hr between B and C, it takes 3 hours to travel from A to C. If it maintains 60km/hr between A and B and 50km/hr between B and C, the journey takes 8 minutes less. What is the distance from A to C via B? Answered by Penny Nom. 





When will the second truck catch up to the first? 
20100522 

From Josie: At 9:00 a.m. a truck leaves the truck yard and travels west at a rate of 45 mi/hr. At 11:00 a.m., a second truck leaves along the same route, travelling at 60 mi/hr. When will the second truck catch up to the first? Answered by Tyler Wood. 





Sammy and his motorboat 
20100511 

From Jordan: Sammy owns a motorboat that travels 4 miles/hour in still water. It goes 12 miles upstream and 12 miles back again (downstream) in a total of 8 hours. Find the speed of the current of the river. Answered by Penny Nom. 





40 miles at 50mph 
20100502 

From gill: if a car travelled 40miles at 50mph, how long would it take? Answered by Penny Nom. 





When are the cars exactly 40 miles apart? 
20100501 

From Maryanne: A car traveling east at 45 mph passes a certain intersection at 3pm. Another car traveling north at 60mph passes the same intersection 25 minutes later. To the nearest minute, figure out when the cars are exactly 40 miles apart. Answered by Penny Nom. 





Two problems 
20100413 

From Dorothy: 1. Explain why the number 123, 456, 789, 101, 112 cannot be a perfect square. (Hint: What is the units digit?)
2. A substance doubles in volume every minute. At 9:00A.M., a small amount is placed in a container. At 10:00A.M., the container is just full. At what time was the container oneeighth full? Answered by Robert Dawson. 





A negative times a negative 
20100325 

From priya: why is minus into minus plus? Answered by Harley Weston. 





What is the speed of the current? 
20100317 

From Carl: If you can row 3 mph in still water and paddle 3 miles upstream and return in 3.6 hours then what is the speed of the current? Answered by Penny Nom. 





At what time would Joan catch Jo? 
20100304 

From Rusty: If Jo left his house at 6:30am traveling at 5mph and Joan left the same house 7:00am traveling at 8mph, at what time would Joan catch Jo? Answered by Penny Nom. 





What time did susan go to bed? 
20100214 

From Sophia: Susan woke up at 7:42 Am to get ready for school. She slept for 10 and 1/3 hours. What time did she go to bed? Answered by Stephen La Rocque. 





A decrease in travel time 
20100130 

From Mike: if a 100 mile trip averages 50 miles per hour, how much distance does one need to travel at 90 miles per hour to decrease travel time by 10% Answered by Stephen La Rocque. 





How long will it take to go 1 mile at 80 mph? 
20100119 

From Susann: How long will it take to go 1 mile at 80 mph? Answered by Penny Nom. 





How fast am I walking? 
20100110 

From KEVIN: IF I WALK 3 MILES IN 28 MINUTES, HOW FAST AM I WALKING? Answered by Penny Nom. 





Gail and Bill drove to the beach 
20100110 

From Nicole: Gail and Bill drove to the beach at an average speed of 50mph. They return home over the same road at an average speed of 55mph. The tip took 30 min less time. How far is the beach from their house? Answered by Stephen La Rocque. 





... the original speed of the car was? 
20091208 

From venkatesh: A car travels a distance of 840 miles at a uniform speed if the speed of the car is increased 10 m/h more ,it takes two hours less to cover the same distance ,the original speed of the car was?
options:75 mh,65 m/h,60 m/h,55 m/h,45 m/h . Answered by Claude Tardif. 





Walking at 4/5 of his usual speed 
20091205 

From venkatesh: walking at 4/5 of his usual speed a man is 10 minutes too late .find his usual time. Answered by Penny Nom. 





At what rate are the people moving apart? 
20091101 

From saira: A man starts walking north at 4 ft/s from a point P. 5 minutes later a woman starts walking south at 5 ft/s from a point 500 ft due east of P. At what rate are the people moving apart 15 minute after the woman starts walking ? Answered by Harley Weston. 





How far will it travel in 45 mins? 
20091027 

From maison: I'm stuck on the formula i dont remeber what it is can you help me out
a car is traveling 80km/h how far will it travel in 45 mins Answered by Robert Dawson. 





Two jets are traveling towards each other 
20091005 

From jake: two jets are traveling towards each other and are 4000 km apart. the rate of one jet is 100 km/h faster than the rate of the other. if the jets pass each other after 2.5 hrs what is the rate of speed of the faster jet? Answered by Penny Nom. 





How long (distance)did it take to stop? 
20090930 

From mary: a car travelling at 50km/h stops in 4 seconds.how long (distance)did it take to stop? Answered by Harley Weston. 





How fast am i going? 
20090928 

From ron: how fast am i going if i drive 40 miles in 20 minutes...what is the formula for figuring this out. Answered by Leeanne Boehm. 





How long would it take the students to arrive at their campsite 
20090918 

From amanda: ..."A group of 5th grade student in New Zealand are going camping. They will hike from Wellingto to Ruapehu. Then they will follow a trail for another 1/2 mile to their campsite." Ok, 1 mile equals 5,280 feet. The class decided one step length is equal to 15 inches and there are 85 steps in 1 minute. Now for the question: About how long would it take the students to arrive at their campsite, if they don't make any stops??? Answered by Robert Dawson. 





Average speed 
20090911 

From john: Sally travels by car from one city to another. She drives for 20.0 min at 68.0 km/h, 40.0 min at 37.0 km/h, and 51.0 min at 77.0 km/h, and she spends 12.0 min eating lunch and buying gas.
What is the average speed for the trip? Answered by Penny Nom. 





Paddling downstream 
20090904 

From Nicole: You head downstream on a river in a canoe. You can paddle at 6 km/h and the river is flowing at 2.4 km/h. How far downstream will you be in 55 minutes? Answered by Penny Nom. 





The distance traveled on a bike 
20090828 

From Dennis: I would like to calculate the distance traveled on a bike based on the size of the tire and on the number of revolutions per minute. This is based on the rider traveling at a constant speed. Answered by Stephen La Rocque. 





Two cars 
20090809 

From Jayna: If a car was traveling 20mph east and another car was traveling 30mph west,
assuming they were 300 miles apart, at what point would they collide at the center? Answered by Penny Nom. 





A boat goes up stream 30 miles and ... 
20090629 

From Mohsin: A boat goes up stream 30 miles and down stream 44 miles in 10 hours. Again it goes up stream 40 miles and down stream
55 miles in 13 hours. Find the rates of the stream and of the boat.
I am confused and unable to get an answer. Please help.
Thanks Answered by Robert Dawson. 





A train crosses a tunnel 
20090625 

From Sabrina: A goods train of length one and half kilometres, is moving at a speed of 27km/hr. find the time taken by it to cross a tunnel of length seven and half kilometres Answered by Penny Nom. 





Driving to school and back 
20090517 

From marylyne: suppose you are late for school and you drive from your house at a constant rate of 70 mph.when class is over, you drive home at a more leisurely 50mph. what is your average speed? Answered by Penny Nom. 





What was her rate of speed? 
20090506 

From Stephanie: beth paddled a canoe to a picnic spot in the river in 2 hours. she traveled up the stream back to the original spot in three hours. the current was two miles per hour.
What was her rate of speed? Answered by Robert Dawson and Stephen La Rocque. 





Decimeters and centimeters 
20090430 

From Jeannette: I cannot convert because of a question that throws me off. For example, A mother African elephant avg's 250 dm in height. A newborn baby African elephant avg's 89cm in height. How many cm shorter is the baby African elephant than its mother? Which one do I convert first? in order to subtract the number from the baby? Answered by Penny Nom. 





Two airplanes are 300 miles apart 
20090422 

From afzalsultan: Two airplanes are 300 miles apart and flying directly towards each other.One is flying at 200 miles per hour, and the other at 160 miles per hour.How long will it take for the two planes to meet Answered by Robert Dawson. 





Passing three cars 
20090416 

From Larry: If 3 cars are going 50 mph, and a fourth car pass the first 3 cars in 200 feet, how fast is the fourth car going? Answered by Stephen La Rocque. 





A man travels a total of 8km in 6 hours 
20090410 

From Kieran: Hello!
I was wondering if you could help me with this question! Thank you
A man travels a total of 8km in 6 hours
if his speed was xkm/4hours in the first stage
then his speed was 8x/2hours in the second part.
If the average speed for the first leg of the journey
was 1.1km/h faster than the second part: find x Answered by Penny Nom. 





How many miles per hour was it traveling? 
20090404 

From Regina: a car traveled 16 miles in 30 minutes. How many miles per hour was it traveling? Answered by Penny Nom. 





A trip at two different speeds 
20090328 

From A student: Good afternoon!
An automobile travels 4 hours at an average speed of 42MPH. How much
longer must the truck travel at an average speed of 55MPH so the
average speed for the total trip will be 50MPH?
Thank you for your assistance! Answered by Penny Nom. 





A 5 ounce object traveling at 60 mph 
20090327 

From James: if a 5 ounce object traveling at 60 mph at 100 feet above the ground, how far will it travel forward before hitting the ground. Answered by Robert Dawson. 





Two racers going around a track 
20090226 

From larisa: One racer makes a complete trip around the track every 28 seconds, while the other racer completes a trip around the track every minute. How many times will the first racer pass the second racer in 30 minutes? Answered by Robert Dawson. 





Fred in his canoe 
20090221 

From Susan: Fred paddled for 4 hours with a 7 km/hr current to reach a campsite. The return trip against the same current took 9 hr. Find the speed of Fred's canoe in still water. (Remember to include correct units) Answered by Penny Nom. 





How long will it take Jake to catch up? 
20090220 

From Rebecca: John is walking 2 miles per hour. Jake leaves home 15 minutes later and is walking 5 miles per hour . How long will it take Jake to catch up ? Answered by Penny Nom. 





Joggong in opposite directions 
20090219 

From Mallory: Emma and her mother jog along a milelong circular path in opposite directions. They begin at the same place and time. Emma jogs at a pace of 4 mi/h, and her mother runs at 6 mi/h. In how many minutes will they meet? Answered by Robert Dawson. 





Cubic centimeters and ounces 
20090206 

From Dawn: 1 syringe contains 5.5cc of medicine & cost $13.50
1 2 oz bottle of medicine cost $17.50
How many cc's in 2 oz, & which is the better deal? Answered by Stephen La Rocque. 





Catching up to the car ahead 
20090206 

From Ashley: Car A passes Car B on a freeway. The driver of Car B decides to speed up to 75 mph and catch Car A, whose driver is maintaining a constant speed.
Looking ahead, the driver of Car B sees Car A go under an overpass oneqarter mile up the road. Exactly six minutes later, Car B catches Car A.
How fast was the car going? Answered by Penny Nom. 





How long will it take to make 50 miles? 
20090126 

From Tamara: An object is traveling at a speed of 45 km/minute. How long will it take to make 50 miles? Answered by Robert Dawson and Stephen La Rocque. 





A tortoise and a hare 
20090120 

From jenna: A tortoise can run with a speed of 0.14 m/s, and a hare can run 20 times as fast. In a race, they both start at the same time, but the hare stops to rest for 1.0 minutes. The tortoise wins by a shell (25 cm).
(a) How long does the race take?
(b) What is the length of the race? Answered by Stephen La Rocque. 





Multiplying negative numbers 
20090115 

From stephanie: hi, I'm currently working in a grade 8 class where the students are
learning about integers. the students were asked to find examples of how
integers are applied in real life. they were able to find aplications for:
adding and subtracting both positive and negative integers. however,
we could not find an example of where two negative integers would be
either divided or multiplied together in real life. For example: (2)(4)= +8.
please help. Answered by Harley Weston. 





Two trains 
20090112 

From Shanise: If train A leaves the train station at noon traveling 45mph and train B leaves the train station at 1pm traveling 65mph, what time will the trains meet? Answered by Robert Dawson. 





The speed of the boat and the river 
20081028 

From Jenn: On the Amazon River in Brazil, a boat goes 50 miles upstream in 3 hours, later the boat returns to the starting point in 2 hours. What is the speed of the boat in still water and what is the current speed in this part of the Amazon? Answered by Penny Nom. 





Travelling home o the train 
20081018 

From nadha: MELISSA reached the railway station at 9.30am.The distance between the railway station and her hometown was 720 km.At what time would she reach her hometown if the train travelled at an average speed of 120 km/h? Answered by Penny Nom. 





If you are driving 40mph, how long does it take to go 2.5 miles? 
20081018 

From Nathan: If you are driving 40mph, how long does it take to go 2.5 miles? Answered by Penny Nom. 





Two planes flying in opposite directions 
20081016 

From samantha: i don't understand how to do this problem.two jets leave denver at 9:00 am one flying at a speed 50 km/h greater than the other, which is traveling west. at 11:00 am the planes are 2500 km apart. find their speeds. Answered by Penny Nom. 





144 square inches 
20080927 

From mike: how much cm is in 144 square inches? Answered by Penny Nom. 





Sample variance: inches to centimeters 
20080922 

From Anita: The average height of a sample of basketball players is 6 feet, 2 inches or 74 inches.
The standard deviation of this sample of players is 4 inches. If each person's height were to be multiplied by 2.54, what would be the value of the resulting sample variance? Answered by Harley Weston. 





Pumping water into a tank 
20080913 

From nadha: A water pump can fill a tank at the rate of 750 litres per hour.A tank has a capacity of
9000 litres. Find the time needed to fill 7/15 of the tank? Answered by Stephen La Rocque. 





Distance, time and rate 
20080911 

From Pauline: During the first part of a trip, a canoeist travels 100 miles at a certain speed. The canoeist travels 25 miles on the second part of the trip at a speed 5 mph slower. The total time for the trip is 5 hrs. What was the speed on each part of the trip? Answered by Penny Nom. 





Converting centimetres to metres 
20080821 

From walter: how do you convert the smaller unit to a decimal of the larger unit and then solve
17 m  130 cm Answered by Penny Nom. 





The best time to teach math 
20080803 

From Kelli: Is there a best time to teach math in the elementary classroom? Has anyone done any research about this? Answered by Stephen La Rocque. 





Running in opposite directions 
20080729 

From maame: if i run six miles per hour and my friend runs four miles per hour and we both run for two hours in opposite directions how many miles apart will we be after the two hours? Answered by Janice Cotcher and Penny Nom. 





Going from 45 mph to 35 mph 
20080709 

From Terry: How long (distance  feet AND time) will it take a car traveling at 45 mph to slow down to a speed of 35 mph? Answered by Harley Weston. 





Two trains 
20080707 

From Elisha: Trains at each end of the 50. km long Eurotunnel under the English Channel start at the same time into the tunnel. Find their speeds if the train from France travels 8. km/h faster than the train from England and they pass in 17 minutes. Answered by Janice Cotcher and Penny Nom. 





A boat travels 20 kms upstream in 6 hrs ... 
20080707 

From vidya: A boat travels 20 kms upstream in 6 hrs and 18 kms downstream in 4 hrs. Find the speed of the boat in still water and the speed of the water current? Answered by Penny Nom. 





Cubic centimeters and milliliters 
20080707 

From Robert: how many milliliters are in 750 cubic centimeters? Answered by Harley Weston. 





How far from each other will they be? 
20080618 

From kerstin: a women jogging at 6 mi/h passes a men biking in the opposite direction at 12 mi/h. if the maintain their speeds, how far from each other will they be 10 minutes after passing? Answered by Stephen La Rocque. 





The length of a shadow 
20080527 

From Simon: A figure skater is directly beneath a spotlight 10 m above the ice. IF she skates away from the light at a rate of 6m/s and the spot follows her, how fast is her shadow's head moving when she is 8m from her starting point? The skater is (almost) 1.6m tall with her skates on. Answered by Stephen La Rocque and Harley Weston. 





55 mi/h for 4 h 
20080521 

From brenda: mary drove her car at 55 mi/h for 4 h. Use the formula d = rt (where d is the distance traveled, r is the rate of travel and t is the time traveled) to determine how far mary traveled. Answered by Penny Nom. 





A crate is launched from an airplane 
20080510 

From Michelle: A crate is launched from an airplane, 75 feet above the ocean, with an initial vertical velocity of 60 feet per second. How many seconds will it take for the crate to hit the water? Round to the nearest hundredth. Answered by Harley Weston. 





How far is it from the top to the bottom of the mountain? 
20080509 

From Matthew: A ski lift carries a skier up a slope at a rate of 2 miles per hour. Following the same path down the mountain, the hiker has a rate of 4 miles per hour. If the round trip took 3 hours, how far is it from the top to the bottom of the mountain? Answered by Penny Nom. 





5 miles per hour for 30 minutes 
20080429 

From Joshua: A boat travels at a constant rate of 5 miles per hour for 30 minutes. How far does the boat go in that time? Answered by Penny Nom. 





Driving home from work 
20080425 

From brittanygrant: brittany house is 37 miles from his job. He leaves at 6:25pm, and drives 49 miles per hour. what time will he get beck home? Answered by Penny Nom. 





45 miles at 50 mph 
20080418 

From Willie: If you travel at 50 mph, how long does it take to go 45 miles? Answered by Penny Nom. 





Jill and Matt run on a 400 meter long oval track 
20080411 

From jamie: Jill and Matt run on a 400 meter long oval track. Jill and Matt each run 10 laps daily and both run in the same lane.
One day Jill and Matt began at the same point, but ran around the track in opposite directions. Jill ran at a constant speed that was 2 meters per second faster than matts constant speed. Jill passed Matt for the first time in 40 seconds. Jill ran at a constant rate of how many meters per second? Answered by Penny Nom. 





Two trains left the city at the same time 
20080411 

From J: Two trains left the city at the same time, traveling in opposite directions. The eastbound train travels for ten hours and the westbound train travels for 5 hours. They are now 1300 km apart. The westbound train's rate is 20 km/hr faster than the eastbound train. Find the speed of each train. Answered by Penny Nom. 





A car is travelling at 80 km/hr speed 
20080410 

From mathew: A CAR TRAVELLING AT A SPEED OF 80km/hr. How much time will take this car to cross a tunnel of 100M Answered by Penny Nom. 





A river boat 
20080409 

From jessica: heres a crazy riddle a river boat that travels 12 mph in still water makes a
pleasure trip to a city upstream and back in 3 hours. If the city is 10 miles aways, what is the rate of the current Answered by Stephen La Rocque. 





A train and a boat 
20080315 

From Sabrina: A railroad bridge is 20m above, and at right angles to, a river. A person in a train travelling at 60 km/h passes over the centre of the bridge at the same instant that a person in a motorboat travelling at 20km/h passes under the centre of the bridge. How fast are the two people separating 10s later? Answered by Harley Weston. 





Parametric equations 
20080305 

From kumi: I have made a picture of a football pass 45 degrees with 30yds and height of 7ft and 4ft. But I am just stuck there. I have stared at the worksheet for soo long. I have no idea how to solve this, and I don't even know where this is going (I don't understand how parametric equations work). Can you help me with this problem?
1.The quarterback of a football team releases a pass at a height, h, of 7ft above the playing field, and the football is caught by a reciever at a height of 4ft, 30yds directly downfield. The pass is released at an angle of 45 degrees with the horizontal with an initial velocity of vo. The parametric equations for the position of the football at time t are given, in general, by x(t)=(vo cosθ)t and y=h+(vo sinθ)t16t^2.
a. find the initial velocity of the football when it is released
b. write the specific set of parametric equations for the path of the football
c.use a graphing calculator to graph the path of the football and approximate its maximum height
d. find the time the reciever has to position himself after the quarterback releases the football Answered by Harley Weston. 





Time and a half 
20080301 

From Travis: Bill receives time and a half for working overtime. If Bill is paid $55 for each hour of overtime, how much is his regular hourly wage? Answered by Stephen La Rocque. 





A package of supplies is dropped from a plane 
20080229 

From beth: An airplane flies west at a speed of 200m/s. A package of supplies is dropped from the plane to some campers. if the plane is at an altitude of 1000meters, how far from the campers should the package be dropped to land near them? ignore wind resistance. Answered by Stephen La Rocque. 





150 decimeters is how many centimeters 
20080229 

From gayle: 150 decimeters is how many centimeters Answered by Penny Nom. 





Two cars are on a collision course 
20080206 

From Danielle: Two cars are on a collision course, heading straight towards each other. One car is traveling 45 miles per hour and the other is traveling 75 miles per hour. How far apart will the two cars be one minute before they collide. Answered by Penny Nom. 





How fast does each travel? 
20080205 

From kRYSTAL: May rides her bike the same distance that leah walks. May rides her bike 10km/h faster than leah walks.
Its takes May 1 hour and Leah 3 hours to travel the sam distance, how fast does each travel? Answered by Penny Nom. 





Driving from Mathville to Bioville 
20080201 

From Ariel: Mahtab took hours to drive from Mathville to Bioville, a total of 485 km.
She drove part by highway at 80 km/h and part by slow roads at 30 km/h.
How many hours did she drive each type of road? Answered by Penny Nom. 





2 km at 5.00 m/s 
20080129 

From Stephanie: How much time does it take for a student running at an average speed of 5.00 m/s to cover a distance of 2.00 km? Answered by Penny Nom. 





How far from the corner will the police catch the car? 
20080127 

From Joel: A car is going down the road at a speed of 90km/h in a 50km/h zone.
As the car passes a corner, a police cruiser sitting there notices it. Five
seconds later the cruiser begins accelerating at 5.0m/s squared.
Assuming that he is able to maintain this acceleration, how far from the
corner will the police catch the car? How fast will the cruiser be going? Answered by Stephen La Rocque. 





Two bikers race on a circular track 
20080117 

From Abby: Two bikers race on a circular track. Biker A can circle the track in 8 minutes, and Biker B can circle the track in 6 minutes. From the start of the race, how many minutes will it be before Biker B overtakes Biker A? Answered by Stephen La Rocque and Penny Nom. 





Driving towards each other 
20080116 

From Shanda: Paul and Charlene are 420 miles apart. They start toward each other with Paul driving 16 miles per hour faster than Charlene. They meet in 5 hours. Find Charlene's speed. Answered by Stephen La Rocque. 





How fast does Kim paddle in still water? 
20080107 

From Fran: Kim paddled a canoe 10 km upstream and then paddled back to his starting point. If the rate of the current was 2 km/h that day and the whole trip took 3.75 h, how fast does Kim paddle in still water? Answered by Penny Nom. 





What is the speed of the plane in still air? 
20080105 

From oscar: A plane flies 400 miles with the wind and 340 miles against the wind
in the same length of time. If the speed of the wind is 24mph, what is
the speed of the plane in still air? Answered by Penny Nom. 





Two cars going in opposite directions 
20071125 

From alexa: two cars leave town at the same time going opposite directions. one of them
travels at 55 mph and the other at 65 mph. in how many hours will they be
150 miles apart? Answered by Penny Nom. 





How many centimeters equal one meter? 
20071115 

From Sherrie: How many centimeters equal one meter? Answered by Penny Nom. 





How do i convert milliliters to grams for water and also for copper sulfate (CuSO4)? 
20071111 

From jenn: how do i convert milliliters to grams for
water and also for copper sulfate (CuSO4)? Answered by Harley Weston. 





Cubic centimeters to cubic yards 
20071110 

From Logan: if i have 188.4cm^3 of concrete how do i change it into cubic yards? Answered by Penny Nom. 





Two cars 
20071104 

From Jalisa: If Car "A" is traveling 50 miles per hour and car "B" is traveling 60 miles per hour, how long will it take car "B" to catch up to car "A" if car "A" had a 15 mile head start. Answered by Penny Nom. 





A car traveled 175m at certain speed 
20071028 

From abdi: A car traveled 175m at certain speed. if the speed had been 20 mph faster,
the trip could have been made in 1 hr less time. find the speed? Answered by Stephen La Rocque. 





Hitting golf balls 
20071003 

From Jessi: Ben is out at the practice range hitting golf balls. How much further will a golf ball with an initial speed of 75.0 m/s go when projected at 45.0 degree than when projected at 30.0 degree? Answered by Stephen La Rocque. 





Will the stone catch up the parachute? 
20071003 

From anoi90: a small parachute dropped from a 30.0 m high cliff falls with a constant velocity of 1.20 m/s. 20.0 s after the parachute is dropped, a stone is dropped from a cliff. Will the stone catch up the parachute before it reaches the ground? (Include numerical proof!) Answered by Stephen La Rocque. 





Peter and Charles mow a lawn 
20070927 

From Nancy: Peter takes 15 minutes longer to mow the lawn by himself than Charles does. Together they can mow the lawn in 18 minutes. How long would it take Charles to mow the lawn by himself? Answered by Stephen La Rocque. 





How many miles per hour was I driving 
20070911 

From Gary: How many miles per hour was I driving to go 37 miles in 13 minutes Answered by Victoria West. 





Safe diving hours 
20070816 

From San: At a popular pier, the average depth of the water at low tide is 1m. The
average depth of the water at high tide is 8m. One complete cycle takes
12h. Given by the equation of y=3.5cosPi/6t+4.5 where y is the height
of the tide in (m) and t is the time in (hour)
*many people dive from this pier during the day. If the water must be at
least 3m deep to dive safely, between what daylight hours should people
dive? Answered by Stephen La Rocque. 





Three runners on a circular track 
20070804 

From Arul: A, B and C run around a circular track starting from the same point simultaneously and in the same direction at speeds of 4 kmph, 6 kmph and 8 kmph respectively. If the length of the track is 400 meters, when will A, B and C meet at the starting point for the first time after they started the race?
4 In the above question, when will they meet for the first time after they started the race? Answered by Penny Nom. 





At what speed does Chuck travel? 
20070727 

From Jessica: Chuck and Dana agree to meet in Chicage for the weekend. Chuck travels
224 miles in the same time that Dana travels 204 miles. If Chuck's rate of travel
is 5 mph more than Dana's, and they travel the same length of time, at what speed
does Chuck travel? Answered by Harley Weston. 





How many ounces in 782 cubic centimetres? 
20070703 

From wilma: how many ounces in 782cubic centimetres Answered by Penny Nom. 





Throwing a ball from the top of a building 
20070612 

From Gilligan: s = distance (in feet)
Building height = 96 feet
t = seconds
Use s = 96 + 80t  16t^2 to answer the question given below.
QUESTION:
After how many second t will the ball pass the top of the building on its way down? Answered by Penny Nom. 





Percent change over multiple periods of time 
20070607 

From Eric: I am trying to show the percent change over multiple periods of time.
Is there a formula for the percent change over multiple periods or will I have to calculate the percent change for each previous period versus the year prior? Answered by Penny Nom. 





What is the speed of the boat? 
20070422 

From Sonja: A boat on a river travels downstream between two points, 20 miles apart, in one hour. The return trip against the current takes 2 1/2 hours. What is the speed of the boat? The answer in the book says 14 mi/hr, but I don't understand how to figure it out. It must be very simple, but I'm stuck. Thank you so much for helping me out. This is a FANTASTIC website! Sonja Answered by Penny Nom. 





Velocity 
20070404 

From Jessica: The speed of the current in a river is 2mph. Jessica travels 20 miles upstream and then 20 miles downstream in a total time of 5 1/3 hr. Find the speed of the boat.
I know you have to use V= d/t, but what is the equation for time because you have to factor in that upstream the boat is slower and downstream the boat is faster? Answered by Penny Nom. 





A delivery driver travels from Belfast to an address in Dublin 
20070404 

From Gerry: A delivery driver travels from Belfast to an address in Dublin.The total distance fro the round trip
was x%.The time required for the forward trip was xx hours.Due to heavy traffic during the return trip an extra xx was required
How much slower was the delivery drivers speed on the return trip?.
I was wondering what equation would you use to solve this question. Answered by Penny Nom. 





Tina swims 4 miles upstream at 1 mph 
20070331 

From Michael: If Tina swims 4 miles upstream at 1 mph and back downstream to the same point to the same point at 4 mph, what is her average speed? Answered by Penny Nom. 





Two busses 
20070315 

From Devon: A bus leaves a station at 1 p.m., traveling west at an average rate of 44 mi/h. One hour later a second bus leaves the same station, traveling east at a rate of 48 mi/h. At what time will the two buses be 274 mi apart? Answered by Steve La Rocque and Penny Nom. 





How long does she have to get out of the way? 
20070223 

From Sharon: How do I solve this? The height h (in feet) of an object that is dropped from the height of s feet is given by the formula h = s  16t^2 , where t is the time the object has been falling. A 6 foot tall woman on a sidewalk looks directly overhead and sees a window washer drop a bottle from the 6 story. How long does she have to get out of the way? Round to the nearest tenth. (A story is 12 feet.) Answered by Penny Nom. 





Increasing speed and decreasing time 
20070218 

From Nigel: I am completely lost...can you help with this: The time, t, to travel a distance, d, at a constant speed, v, can be obtained from the formula: d = vt. If the speed is increased by x, find an expression to represent the decrease in time to travel the same distance. Answered by Stephen La Rocque. 





Centimeters to cubic meters and grams to kilograms 
20070214 

From Colleen: A box of balls measures 120cm by 20cm by 20cm and weighs 48 g. One thousand boxes = x cubic meters and weighs x kilograms. Also, one million boxes = x cubic metes and weighs x kilograms. One billion boxes = x cubic meters and weighs x kilograms. Solve for x. Answered by Stephen La Rocque. 





Square centimeters 
20070212 

From Ivan: how many square centimeters are in a rectangle that is 210 centimeters long by 39 centimeters wide.? thank you Answered by Karen McIver and Melanie Tyrer. 





Difference in scanning time 
20070208 

From Lisa: Boat 1 with 12,000 items on board with 7 days docking time limit Boat 2 with 12,000 items on board with 1 day docking time limit
Each item has to be scanned. We want to find out the difference in scanning time (in minutes and seconds). We tried this formula but with 60 minutes in one hour, 60 seconds in one minute, we are not sure if this formula is accurate. Answered by Penny Nom. 





Romeo is throwing pebbles 
20070208 

From Jessie: Romeo is chucking pebbles gently up to Juliet's window, and he wants the pebbles to hit the window with only a horizontal component of velocity. He is standing at the edge of a rose garden 4.5m below her window and 5.0m from the base of the wall. How fast are the pebbles going when they hit her window? Answered by Stephen La Rocque. 





A boat travels 60 miles downstream in the same time it takes to go 36 miles upstream 
20070127 

From Liz: A boat travels 60 miles downstream in the same time it takes to go 36 miles upstream. The speed of the boat in still water is 15 mi/h greater than the speed of the current. Find the speed of the current. Answered by Stephen La Rocque. 





A college student jogs from his home to the beach 
20070123 

From Garmani: A college student jogs from his home to the beach at 8 miles per hour. He visits with his friends on the beach for 4 hours, and then his friends drive him home at the rate of 40 miles per hour. If the student returns home after 6 hour, what is the distance from his home to the beach? Answered by Penny Nom. 





What is the speed of each boat per hour? 
20070122 

From Garmani: Two tuna boats leave the same port traveling in opposite directions along the west coast of the United States. One boat travels 5 miles per hour faster than the other. At the end of one day's travel they are 1,080 miles apart. What is the speed of each boat per hour? Answered by Penny Nom. 





What is his rate of walking for the entire trip? 
20070112 

From Garmani: A man walks 500 feet at 4 miles per hour and returns to the starting point at 3 miles per hour. What is his rate of walking for the entire trip? Answered by Stephen La Rocque. 





What is the speed of the current? 
20070107 

From Bob: A motorboat can maintain a constant speed of 16 miles per hour relative to the water. The boat makes a trip upstream to a certain point in 20 minutes; the return trip takes 15 minutes. What is the speed of the current? Answered by Haley Ess. 





I want to convert milliliters into grams. 
20061214 

From Kenchotenzin : I want to convert milliliters into grams. Answered by Penny Nom. 





Cary was going to meet Jane at the airport, ... 
20061211 

From Carmen: cary was going to meet jane at the airport, if he traveled 60mph, he would arrive one hour early, and he traveled 30 mph, he would arrive one hour late. how far was the airport? recall: distance=speed(time) Answered by Stephen La Rocque. 





The Metra and the Amtrack 
20061203 

From Amy: A Metra commuter train leaves Union Station in Chicago at 12 noon. Two hours later, an Amtrak train leaves on the same track, traveling at an average speed that is 50 miles per hour faster than the Metra train. At 3PM the Amtrak train is 10 miles behind the commuter train. How fast is each going? Answered by Stephen La Rocque and Penny Nom. 





A trip on the Grand River 
20061130 

From Kristy: Romo decided to make a 28km trip up and 28km trip down the Grand River. the speed of the current is 3km. one way Romo travelled with the current and the other way against the current. During his trip, Romo stopped for half an hour for lunch. if Romo's total trip lasted 6hours, how fast did he travel? Answered by Stephen La Rocque. 





Going from one town to another 
20061104 

From Austin: Going from one town to another,a man drives his car at 35 miles an hour and returning he drives at 25 miles an hour. the round trip takes 6 hours. Find the distance between the towns. Answered by Stephen La Rocque. 





Paddeling on the Alleman River 
20061031 

From Anita: Len is planning a threehour trip down the Alleman River and back to his starting point. He knows that he can paddle in still water at 3 mph and that the rate of the current is 2 mph. How much time can he spend going downstream? How far downstream can he travel? Answered by Penny Nom. 





Flying with and against the wind 
20060706 

From Tim: When a plane flies with the wind, it travels 800 miles in 4 hours. Against the wind it takes 5 hours to cover the same distance. Find the rate of the plane in still air and the rate of the wind. Answered by Stephen La Rocque. 





A boat travels 60 miles upstream ... 
20060528 

From Teenarick: A boat travels 60 miles upstream against the current in 3 hours. It takes 2 hours for the return trip. Find the speed of the boat in still water. Answered by Penny Nom. 





Small pipes and large pipes 
20060509 

From geece: A large fresh water reservoir has two types of drainage system. Small pipes and large pipes. 6 large pipes, on their own, can drain the reservoir in 12 hours. 3 large pipes and 9 small pipes, at the same time, can drain the reservoir in 8 hours.
How long will 5 small pipes, on their own, take to drain the reservoir? Answered by Penny Nom. 





Wes and Tony live 360 km apart. 
20060401 

From Thiru: Wes and Tony live 360 km apart. If Wes travels at 80 km/h towards Tony. And Tony travels at 100 km/h towards Wes, how long will it take before they meet. Answered by Penny Nom. 





Related rates and an oil spill 
20060212 

From Brandon:
An Oil Tanker Spills 100,000 cubic meters of oil, which forms a slick that spreads on the water surface in a shape best modeled by a circular disc is increasing at a rate of 3m/min (it doesn't state what is increasing at 3m/min, so I'm assuming Radius until I can ask my teacher.) At t=T, the area of the "circular" slick reaches 100pi Sq. meters.
A) how fast is the area of the slick increasing at t=T
B)How fast is the thickness of the slick decreasing at t=T
C)Find the rate of change of the area of the slick with respect to the thickness at t=T.
Answered by Penny Nom. 





60.5 ft at 90 mi/hr takes how long? 
20060113 

From Bree: A ball travels over 60.5 ft at 90 mi/hr. How fast does the ball travel? Answered by Penny Nom. 





what is 5'7 
20051126 

From A student: what is 5'7" inches in cm? Answered by Harley Weston. 





Inches and millimeters 
20051008 

From Ron: You know they say 14mm = 9/16" or something of that nature, i need to know exactly how this is done. Answered by Chris Fisher. 





Inches and millimeters 
20050930 

From A student: how many inches are there in mm? For example 30x40 mm = how many inches. Answered by Penny Nom. 





Centimeters, millimeters and milliliters 
20050419 

From A student: How many milliliters in a centimeter? Answered by Penny Nom. 





Doubling time 
20050312 

From Nick: Looking for the equation to how many years it will take to double the population given the growth rate is 7%. Answered by Penny Nom. 





Nine minutes 
20040902 

From A student: You have two hour glassesone measures 7 minutes and one measures 4 minutes.How can you time 9 minutes? Answered by Penny Nom. 





130 cc. is ? 
20040820 

From Ayrn: 130 cc. is ?
I have to put 130cc. of petroleum in a bucket how much exactly is that?
Also 110 cc.?
I have to also put 110cc. wood alcohol in a bucket aswell! Answered by Penny Nom. 





425 cc's of a saline solution 
20040330 

From Julie: 425 cc's of a saline solution is equal to how much in lbsweight?? Answered by Harley Weston. 





Distance, time and rate 
20040309 

From Peter: A car travels from one city to another at the speed of 32mph, if it had gone 4mph faster it could have made the trip in one half hour less. How far apart are the cities?
Answered by Penny Nom. 





Driving from Sarnia 
20040211 

From Jane: "Crystal drove from Sarnia at 80km/hr. Emily left Sarnia one hour later and drove along the same road at 100km/hr. How far from Sarnia did Emily overtake Crystal?" Answered by Claude Tardif. 





Three times a year 
20040209 

From Graham: What is the term for a report that is submitted three time a year or at the very least a prefix term for one third Answered by Harley Weston. 





The London marathon 
20040127 

From Nina: After a years training, Minnie Midriffe increased her average speed in the london marathon by 25%. By what percentage did her time decrease?o Answered by Penny Nom. 





Ounces into cubic centimeters 
20040127 

From A student: how do you convert ounces into cubic centimeters? Ex: how does 12 oz. change into cc. Answered by Penny Nom. 





Business trip 
20031219 

From Ameer: A businnessman drives from Washington, D.C., to Boston, a distance
of 442 miles, and then makes the return trip. On the way to Boston,
he drives 65 miles per hour, taking an 1hour rest stop during the
drive. After finishing his business in Boston, he make the return
trip driving at 60 miles per hour and takes a 45minute rest stop
halfway through the trip. Which leg of the journey, Washington, D.C.
to Boston, or Boston to Washington, D.C., takes the longer time? Answered by Penny Nom. 





The hour hand and the minute hand 
20031217 

From Minnie: When you are looking at the clock at 12:00 the hour hand and minute hand are exactly together. (one on top of the other). Between 1:00pm and 1:15pm there is another time when the hour and minute hands are exactly together again. Answered by Penny Nom. 





How much time? 
20031029 

From Lori: I am a elementary teacher 36 math. We have just implemented the Houghton Mifflin Math curriculum. It seems to be quite difficult for most of our students. In order to get through all the material we need to do a lesson a day. Although the students are not getting the material that fast. Should we move on without all the students understanding the material or should we wait and remediate until they get it and be behind for the year. This isn't just a few kids its most of the kids. We are also suppose to teach to all the standards so if we don't get to them the students will not do well on the standardized tests. Answered by Diane Hanson. 





One million seconds 
20030904 

From Vince: If you can write a number each second for one million seconds, how many hours would it take? Answered by Penny Nom. 





A boat travels 12 km upstream... 
20030903 

From Sohaib: A boat travels 12 km upstream and back in 1 hour 45 minutes. If the speed of the current is 3km/hr throughout, find the speed of the boat in still water, giving your answerÝcorrect to 3 decimal places. Answered by Penny Nom. 





Sunshine? 
20030711 

From lori: It is noon, your lunch hour, but you cannot go out because there is a terrific hailstorm. Turning on your radio you hear the weathercaster predict that the hail will change to rain and that it will pour all day today. How can you determine whether the sun will be shining in 36 hours? Answered by Claude Tardif. 





______cm=0.048km 
20030227 

From Antonette: ______cm=0.048km Answered by Penny Nom. 





Two airplanes leave Dallas 
20030206 

From A student: TWO AIRPLANES LEAVE DALLAS AT THE SAME TIME AND FLY IN OPPOSITE DIRECTIONS. ONE AIRPLANE TRAVELS 80 MILES PER HOUR FASTER THAN THE OTHER. AFTER THREE HOURS, THEY ARE 2940 MILES APART. WHAT IS THE RATE OF EACH AIRPLANE? Answered by Penny Nom. 





A train with 2 cars 
20030204 

From Michael: A train with 2 cars is traveling at a speed of 80 km/hr from town X to town y, located 800 km from each other. At the same moment that the train departed, a passenger started to walk back and forth from one end of car B to the other at a speed of 100cm/sec. Arriving in town Y, the passenger had already gone and returned 720 times. The length of car A is that of car B plus one fourth of the length of the locomotive, and the length of the locomotive equals the length of Car A plus one fifth of the length of car B. What is the total length of the train? Answered by Penny Nom. 





Miles per hour 
20021128 

From Liz: If a car has traveled 16 miles in 30 minutes, how many miles per hour did they go? Answered by Penny Nom. 





Cubic centimeters 
20021107 

From Rita: Was in emergency room yesterdayMD aspirated 40cc of fluid from my kneewhat does a "cc" equate to? Answered by Penny Nom. 





10 hours before 7:15 
20021027 

From Jessica: It is evening 7:15. What time would it be 10 hours earlier? Answered by Penny Nom. 





How long will it be before you reach your friend? 
20020916 

From Margaret: Your friend runs at 8 miles per hour and you drive at 40 miles per hour, hence the diatance between you is decreasing at 32 miles per hour. You firend left 2 hours before you so how far has he gone in that 2 hours? How long will it take for the distance between you to decrease to 0 miles if the distance is decreasing at 32 miles per hour? Answered by Penny Nom. 





A million sheets of 30 cm long paper 
20020915 

From Jennifer: if you put a million sheets of 30 cm long paper end to end, how many kilometer long would the paper be from begining to end? Answered by Penny Nom. 





Use a 4 four times 
20020912 

From Amanda: The question is what is if you can only use a 4 four times and get the answer 12, 10, and 6 Answered by Claude tardif. 





A box that holds 22.4 liters 
20020707 

From Jon: How do I find the measurements required to make a box that holds 22.4 liters of something? Answered by Penny Nom. 





Ounces and cubic centimeters 
20020530 

From Martin: How many ounces are in 600cc of liquid? Answered by Penny Nom. 





Trains and cracker boxes 
20020429 

From Lindsay: 1)Two trains are 250 miles apart on the same track heading towards eaxh other at 7AM The first train travels at 55mph, the second at 75mph. At what time would they crash? 2)A cracker box measures 12 by 2 by 18 inches. The company wants to double the amount of crackers, but keep the shapes the same[similar] Find the new length[nearest tenth of an inch] Answered by Penny Nom. 





Conversion of units 
20020429 

From Matt: I am having trouble finding a workable equation for the following problem, particularly the conversion of two systems of measurement. The question states that there are 27 grams of salt in a kilogram of seawater. And it asks how many tonnes (1 tonne = 1000 kilograms) of salt are there in one cubic kilometer of ocean. It also says that the density of seawater is 1.1 g/cm3. What is the equation and how do I figure out how many kilograms there are in a cubic kilometre? Answered by Harley Weston. 





A test drive 
20020423 

From Jennie: At 9 A.M. a test car driving at a constant speed passes a marker 50 miles from it's starting point. At noon the car is about 130 miles from the marker. If the test drive ends at 1:30 P.M., how far will the car be from its starting point? Answered by Penny Nom. 





Mr. Byrd's drive to work 
20020322 

From Mr. Bollen: Mr. Byrd leaves his house at 7:00am to go to work. If he drives 40 mph he will arrive 3 minutes late and if he drives 60mph he arrives 3 minutes early. At what speed will Mr. Byrd have to drive in order arrive exactly on time. Please describe how you arrived at your answer. Answered by Claude Tardif and Penny Nom. 





15 miles at 13 miles per hour 
20020312 

From Rich: If I were traveling 15 miles at 13 miles per hour how long will it take? Answered by Penny Nom. 





My 1978 Chevy has a 350 cubic inch engine 
20020311 

From Sharon: If my 1978 Chevy has a 350 cubic inch engine, about what size engine would that be in liter? Answered by Penny Nom. 





The best time to teach math 
20020310 

From West: My name is West. I teach 4th grade. I would like to know if there is any research which tells about the best time to teach math. Should it be taught in the a.m. or p.m. Answered by Walter Whiteley. 





Number conversions and averages 
20020203 

From A student: A table has the measurements of 1.6m by 2m, how much material is needed to cover table? I converted to cm then multiplied but got an answer of 32000cm ,so I divide by 100 to get to metres  the answer was 320 which I know is wrong  please explain!! Also I need to explain in my own words what an 'average' is and I am struggling. Answered by Penny Nom. 





The famous "train problem" 
20020112 

From Karen: How do you solve the famous "train problem"? For example, 2 trains leave different stations at the same time. One is traveling at 50 mph and the other at 40 mph. How long does it take them to meet? Answered by Penny Nom. 





Negative times negative is positive 
20011026 

From Mary: I have a question about adding and multiplying positive and negative numbers. When we add two negative numbers the answer is negative BUT when we multiply two negative numbers the answer is positive. I don't understand. Why? Answered by Penny Nom. 





Metric units 
20011025 

From Kelly: i am helping my kids out with school work and don't remember meters,centimeters decimeters and all those. We have to change meters into cm.....and so on..........is there a place on the web to look for some kind of help in these questions Answered by Penny Nom. 





60 seconds in a minute 
20011011 

From Andy: I am a fourth grade teacher. Yesterday my students asked "Why are there 60 seconds in a minute?" Which also led to 60 minutes in an hour? I have had trouble determining why the number 60? Any help would be appreciated. Answered by Penny Nom. 





Julia goes to work 
20010925 

From Karyna: On one October morning, Julia rides her bike (at 12 miles per hour) from her home to her friend Ida's house; then the two of them walk (at 6 miles per hour) to work. If it takes an hour for Julia to go the 10 miles from her home to work, how far does she walk? Answered by Penny Nom. 





David's wages 
20010924 

From Kimberlee: My math question is David earns $6.00 per hour plus $9.00 for every extra hour he works over 40 hours per week. If David earned $285.00 last week, how many extra hours did he work? Answered by Penny Nom. 





Ray and Jane 
20010906 

From A student: If Ray and Jane live 150 miles apart and they both leave their house at the same time, Ray goes 30 mph the whole time and Jane goes 50 mph the whole time how many miles are they from Ray's house when they meet? And what is the exact travel time untl they meet. Answered by Penny Nom. 





How far does the fly fly? 
20010807 

From Harold:
6 MPH 4 MPH
Rachel  Eli
10 Miles apart
The fly is on Rachels handlebars. The fly is scared so it flys back and forth at 20 MP H. How far has the fly flown when Rachel and Eli meet? f Answered by Penny Nom. 





Hours worked 
20010718 

From Carlos: I have a simple question:whats the formula to transform time into decimals? more exactly im working on a spreadsheet and i want to be able to type in for example hours worked: 11 11:30 pm and a formula would tell me 12.5 hours how do i do it? Answered by Patrick Maidorn. 





When did the man go out? 
20001214 

From Rajesh: A man goes out in time between 5 and 6 and when he comes back he observes that two hands have interchanged position. Find when the man did go out? Answered by Penny Nom. 





Three problems 
20001214 

From Sarah: Hi, my name is Sarah, and I'm asking this question on behalf of niece who is in secondary two. Thank you. Q1. What is the angle formed by the hour hand and the minute hand of a 12 hour clock at 5.50pm. . . . Answered by Penny Nom. 





A colony of bacteria 
20000422 

From Nicci Demmin: Suppose that the bacteria in a colony can grow unchecked, by the law of exponential change. The colony starts with one bacterium and doubles every half hour. How many bacteria will the colony contain at the end of 50 hours? Answered by Penny Nom. 





A negative times a negative 
20000229 

From Michael J. Butler: I have reviewed the answer in relation to the question of why (3)x(2)=6; however, I am still not able to properly explain the reasoning to my son, Jonathan, who is in grade 7. I want him to understand the reason for the rule that the multiplication or division of two negative numbers equals a positive number. Can you help? Answered by Chris Fisher. 





Jogging up a hill 
20000217 

From Aaron Williams: A man jogs down the hill at 6 miles per hour and back up at 4 miles per hour. The total time that he travels is 5/4 hours. What is the total distance that he jogged. The solution is supposedely 3 miles, but i believe that it is 6. Can you help me? Please. Answered by Claude Tardif. 





Age in minutes 
19991121 

From Mesha Jackson: How old would I be in minutes if I were 12 Answered by Penny Nom. 





A goofy clock 
19991120 

From Kate: While repairing a watch, a jeweler removed the hands and inadvertently replaced the hour hand on the min. spindle and vice versa. he set the hands to read 2:00pm, which was the correct local time when I picked up the watch. A few minutes later, I noticed that the hands were taking goofy positions. What was the first time thereafter that the watch would show the correct local time? Answered by Chris Fisher. 





A bike race 
19990423 

From Bill Gepford: Bill was in a bike race and his friend kyle calculated that if he went 15mph that he would cross the noontime checkpoint one hour early but if he rode 10mph he would arrive one hour late. How far away is the checkpoint? Answered by Penny Nom. 





Ounces and milliliters 
19990417 

From Tony Rizzi: I'm mixing a formula of: 48 oz distilled water. 15 grams of Hydroxy Ethyl Cellulose GR (powder) 30 grams of Hydroxy Ethyl Cellulose MR (powder) 200 grams of Barium Sulfate (powder) 1000 grams of Calcium Hydroxide (powder) After mixing, I need to estimate the amount of each ingredient that fits in a 3ml syringe. And how many syringes I can fill? Answered by Harley weston. 





Converting Metric Measurements 
19990408 

From Rick: Do you have any simple explanations for converting Metric measurements to other Metric measurements?? What helpful hints do you also have for a 5th Grader... Answered by Penny Nom. 





An airplane problem 
19990308 

From B.M.R.: A plane left New York and headed East to its destination 3600 miles away across the Atlantic. On the way back its speed was boosted by a 50 mph tail wind and it arrived an hour early. What was its normal speed? Answered by Jack LeSage. 





Metric Conversion 
19990307 

From TDestra: Please help to answer this question: Is a cubic centimeter equivalent to milligrams or milliliters, and how many? Also, is it a liquid measure? Answered by Penny Nom. 





Converting mm's to inches 
19990222 

From Paul White: It has been a long time since high school and I do not remember how to convert mm to inches. Could you please tell me what this would convert to in inches? 210 X 254 mm. Answered by Chris Fisher. 





Centimetres 
19981111 

From Vicky Caldwell: I work in Carpet Manufacturing and I need to know how to figure the calculation for a roll of carpet in centimeters. For example: a 12 x 100 roll of carpet equals 133.34 square yards, which is 100 linear ft. and 1,200 square foot. Can you please tell me how I would figure to get CENTIMETERS??????? Answered by Jack LeSage. 





Nickles on the Highway 
19980922 

From Ronnie Mac Donald: How many nickels would it take to cover 226km of highway,each nickel is 2cm in diameter? Answered by Penny Nom. 





Hour Hand Movement 
19980419 

From Chris and Angela Bradley: My wife and I are haveing an argument over the answer to this question, what is the total number of degrees through which the hour hand of the clock moves in 3 hours and 18 minutes? Thanks in advance. Answered by Chris Fisher. 





(3)x(2) 
19951025 

From Azmat: Why is (3)x(2) = 6? Answered by Herley Weston and Ed Giesbrecht. 





100 centimètres 
20021113 

From Un élève: je voudrais savoir la contenance de 100 centimètres cube en litre? Answered by Diane Hanson. 

