Math Central - mathcentral.uregina.ca
Quandaries & Queries
Q & Q
. .
topic card  



list of
. .
start over

46 items are filed under this topic.
Gravel for a French Drain 2020-04-17
From Ray:

** I am wanting to add 2 French Drain's in my yard. The 1st drain will be 25 ft. long, 8 in wide and 18 in deep. The pipe I'm using is 4in. in diameter. I'm trying to figure out how many yards of clean gravel I will need for this project?

** The 2nd French Drain will be 100 ft in Length, 10in wide and 18 in deep. I will also be using the 4in in diameter pipe for this drain. I am needing to see how many yards of clean gravel, I'll need for this drain? Any assistance would be greatly appreciated!! Thank you!!

Answered by Harley Weston.
The length of a train 2017-04-24
From Stefano:
If a freight train is coming towards you and you were traveling at 85 miles an hour and it takes 35 seconds for the train to pass you how long is the train

Figure 50mph for train

Answered by Penny Nom.
A train from Erie to New York 2016-07-14
From carol:
a train leaves Erie with twice as many women as men. At York, 17 men get on and 16 women . How many men and women were originally on the train?off. There are now the same number of men as women
Answered by Penny Nom.
Water flowing through a rectangular drain 2016-01-08
From Tiffany:
the cross section of drain is a rectangle 30 cm wide. If water 3.5 cm deep flows through the drain at a rate of 22 cm/s, how many litres of water will flow through in one minute?
Answered by Penny Nom.
A train trip 2015-03-23
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.
One train overtaking another 2013-11-11
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.
Can the result of the calculation be 2? 2012-02-09
From Thomas:
You have the digits 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9 in a random order side by side and put randomly between two digits a colon, so that a division comes into existence. Can the result of the calculation be 2?
Answered by Robert Dawson and Chris Fisher.
Two trains passing each other 2011-12-07
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.
A pipe in a ditch 2011-05-19
From Jim:
How many cubic feet of stone will it take to fill to six inches around a 4 inch pipe in a ditch 128 ft long x 20 in wide?
Answered by Penny Nom.
A train passes a car 2010-10-24
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.
2+3 =10 and 7+2=63 and ... 2010-03-01
From brenda:
if 2+3 =10 and 7+2=63 and 6+5 =66 and 8 +4 = 96 then 9+7+ ??????
its driving me crazy !!

Answered by Penny Nom, Claude tardif and Melanie Tyrer.
A trillion grains of rice 2009-09-14
From akaila:
can 1trillion rice grains fit in a classroom with the area of 144.4m3
Answered by Penny Nom.
A train crosses a tunnel 2009-06-25
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.
Two trains 2009-05-18
From chris:
Train A passes a station at 3:15am going 40mph. Train B passes the same station at 3:27am going 50mph. At what time will Train B catch up with Train A?
Answered by Stephen La Rocque.
The scale for a model train 2009-03-13
From Shelly:
Lindy is planning to build a model of a train using a scale where 2 inches represents 25ft. If the train is 60 feet long, what is the length in inches that Lindy should build the model of the train?
Answered by Stephen La Rocque and Penny Nom.
Two trains 2009-01-12
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.
A cone shaped pile 2008-10-10
From Nadine:
I have a pile of wheat in the shape of a cone. I would like to know how much wheat I have. I have found the equation "V=1/3 pie r squared h" , but it dosn't work! The pile is 7 feet high, diameter is 50 feet, circumference is 185 feet. I also measured the slope 19feet. (Probably not needed) You need to know that wheat weighs 60 pounds per bushel, and I would like to know how many bushels I have. Even if I could receive the # of Volume Bushels, I could convert that. Can you help me??
Answered by Stephen La Rocque.
How many litres of rain is this? 2008-09-01
From Todd:
If i have 10mls of rain over one square metre how many litres would I and how do I do the maths for this?
Answered by Penny Nom.
Two trains 2008-07-07
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.
Two trains left the city at the same time 2008-04-11
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.
1 foot of snow = how much rain 2007-09-25
From Lisa:
1foot of snow = how much rain
Answered by Penny Nom.
Comparing flow rates of two pipes 2007-07-14
From Kenneth:
If two water pipes are 3 feet long, but one of them has a 1 foot diameter and the second has a 1 1/2 foot diameter, what simple mathematical method can be used to determine how much faster one pipe can drain water than the other pipe?
Answered by Stephen La Rocque.
Relating volume to depth in a cylindrical container 2007-04-19
From Dan:
I have a cylindrical polyethylene rain barrel 23" in diameter and 35" high. If I've calculated correctly thus far, its volume is:

14, 547.49 cubic inches (or 8.418686 cubic feet or 0.31 cubic yards)

and could, ideally, contain 62.6 gallons of rain water whose weight would be 525.32 lbs. (62.4 lbs./cubic foot X 8.418686).

I'm having difficulty relating inch depth markings on the side of the barrel to volume capacity; i.e., how many inches in depth in a cylinder of the size given would = how many gallons (or quarts) of water. The barrel stands upright on its end and is, thus, 35" high when oriented in this fashion, much as a 55-gallon oil drum appears when similarly stowed. Dan Watley

Answered by Stephen La Rocque.
Calculating rainwater volume 2006-12-30
From Mark:
Trying to calculate 1" rainfall on a 1000 sq' roof=how many gallons of water would collect in our cistern.
Answered by Stephen La Rocque.
How many trains of length 5 are there? 2006-11-20
From Shea:
A "train of length 5" is a row of blocks whose combined length is 5. Here are some examples: 1-2-2, 2-1-2, 1-3-1, 5, 1-4. If you use identical blocks in a different order, this is a separate train. How many trains of length 5 are there? Come up with a formula for the number of trains of length n.
Answered by Penny Nom.
Two trains left the station at the same time and traveled in opposite directions. 2006-11-18
From Tori:
Two trains left the station at the same time and traveled in opposite directions. The E train averaged 130 km/h. The A train's speed was 110 km/h. In how many hours were they 480 km apart?
Answered by Stephen La Rocque.
Volume of rainfall 2006-07-18
From Randy:
Calculate the amount (in gallons)of rainfall .98 inches will put over an area of 3.76 acres.
Answered by Stephen La Rocque.
A train model is created using a scale of 1:60 2006-01-01
From Jennifer:
An "n gauge " train model is created using a scale of 1:60. If an actual train engine, the "K-4" an early twentieth-century engine,is 45 feet long, what is the length of an "N gauge" model of the engine in inches?
Answered by Penny Nom.
Two puzzles 2004-07-13
From Fred:
A young man's car developed a flat tire while he was driving along a deserted street. He pulled over to the curb and did all the usual things; removed the hub cap; unscrewed the lugs and rested them carefully in the hub cap, jacked up the car. As he was putting the spare tire onto the axle he accidentally kicked the hub cap. The lugs rolled out, and all five of them rolled down a nearby grate. Peering through the bars of the grate the man thought he could see the lugs about 6 feet below in a shallow water puddle. He had a problem, how do you think he solved it?

It is noon, your lunch hour, but you can not 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 the sun will be shining in 36 hours? Justify your answer.

Answered by Penny Nom.
Three parabolas 2004-04-24
From A tutor:

I am a maths tutor. One of my year 12 students has given me this assignment. Many parts are ambiguous. I am trying to determine the equation of the line segment AB. Given that A has an incline of 10 degrees below the horizontal, I am assuming that this parabola (although you can only see part of it) has been rotated 10 degree clockwise. Am I right in assuming this? If so, how do I derive the equation of the parabola as it will then not fit the general form y = ax squared +bx +c of a parabola.

Also, how is one expected to find the x coordinate of D without the equation of this parabola. To find the equation you need the x-coordinate and therefore be able to find another point on the parabola in order to derive the equation using simultaneous equations.

Answered by Penny Nom.
An arc on a train track 2004-02-15
From A student:
I'm trying to build a route in a train simulator program. I have a curve to the right (an arc, in other words) with a length of 25 meters and the radius is 1,500 meters. Let's say point P is the beginning of the curve (arc) and point Q is the end point of the arc. Then picture a tangent to point P. I need to find the length of a line perpendicular to that tangent that runs to point Q (the end of the curve/arc).
Answered by Penny Nom.
A problem with lugs 2003-07-11
From Lori:
A young man's car developed a flat tire as he was driving along a deserted street. He pulled over to the curb and did all the usual things: removed the hub cap, unscrewed the lugs and rested them carefully in the hub cap, jacked up the car. As he was putting the spare tire onto the axle he accidentally kicked the hub cap. The lugs rolled out, and all five of them fell down a nearby grate. Peering through the bars of the grate the man thought that he could see the lugs about 6 feet below in a shallow water puddle. He had a problem. How do you think he solved it?
Answered by Penny Nom.
Gallons of rain 2003-04-25
From Jocelyn:
If you have a surface of 6500 square feet and 1 inch of rain falls on the surface, how many gallons of water does this equal?
Answered by Penny Nom.
A train with 2 cars 2003-02-04
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.
Two rate problems 2002-09-30
From Rebecca:
  1. There are two small holes in the bottom of a tub filled with water. If opened, one hole will empty the tub in three hours; the other will empty it in six hours. If both holes are opened at the same time, how long will it take to empty the tub?

  2. An airplane flies 400 miles per hour in calm air. It can cover 900 miles flying with the wind in the same time that it can cover 700 miles against the wind. What is the speed of the wind?

Answered by Penny Nom.
Trains and cracker boxes 2002-04-29
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.
The famous "train problem" 2002-01-12
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.
Who owns what pet? 2001-10-03
From A parent:
Don, Frank, Jenny, and Ken each come from one state, either Alaska, Maine, Montana, or Oklahoma. They each speak one primary language, either English, french, Russian, or Spanish. And they each have one of four pets, a chinchilla, a dog, a hamster, or a turtle.

Figure out which language and what pet each of the four people have, using the following clues.

Answered by Judi McDonald.
Shape, symmetry, measurement and space 2001-02-24
From Marilyn:
I have to write in detail about how young children learn about shape, symmetry, measurement and space. It is not activities I need it is how the children learn. How/why their brain takes it all in
Answered by Walter Whiteley.
Running Through a Train Tunnel 2000-04-01
From Eugene Chan:
A man is running through a train tunnel. When he is 2/3 of the way through, he hears a train that is approaching the tunnel from behind him at a speed of 60 mph. Whether he runs ahead or back, he will reach an end of the tunnel at the same time the train reaches that end. At what rate, in miles per hour, is he running? (Assume he runs at a constant rate.)

I think the answer (12 mph) is wrong. Also, I believe it should read 1/3 of the way through, but don't know how to prove it. Could you come up with some way to prove it, please? I would really appreciate it.

Answered by Penny Nom.
Word problems 2000-03-31
From Amy:
  1. a north bound train left at noon. four hours later a south bound train left the same station. at 5 o'clook they were 160 miles apart. what was the rate of both if the north bound train was going 20 miles faster than the other one.
  2. clark's final exam was given 5 times the weight of the weight of a weekly test. the avgerage of 15 weekly test was 91. the overall weighted average was 85. what did he make on the final.

Answered by Penny Nom.
Passing trains 1999-12-10
From Nancy:
Two trains, each of 80 cars, must pass on a single track which has a deadend siding. How can they pass if the siding can only hold a locomotive and 40 cars?

I do not understand this...help. It will be due monday. I thought it would be simple if the siding could hold 80 cars.
Answered by Penny Nom.

Large Numbers 1999-04-05
From CK:
Hello. I need a lesson plan for grades 4 to 7 dealing with the concept of large numbers. Specifically, how to teach scientific notation. The lesson plan has to deal with the following: the size of the universe is so huge that is is almost beyond the ability of the mind to comprehend. One way is to measure...
Answered by Chris Fisher.
Smith, Rodriguez and Jones 1996-11-07
From Rafayel Ambartsumyan:
On a train, Smith, Rodriguez, Jones are the fireman, brakeman, and engineer, but not in that order. Also aboard the train are three businessman who have the same names, a Mr. Smith, a Mr. Rodriguez, and a Mr. Jones. ..... Who is the engineer?
Answered by Penny Nom.
Un bénéfice de 5% 2008-03-11
From mahiques:
Un propriétaire decide de vendre deux parcelles de terrains pour un montant total de 141750 F. Il fait un bénéfice de 15% sur la première et une perte de 10% sur la deuxième. L'ensemble de la transaction lui a rapporté un bénéfice de 5%.combien a-t-il vendu chacune des parcelles ?
Answered by Pierre-Louis Gagnon.
Des grains de blé 2007-01-06
From Renaud:
Remplir un échiquier avec des grains de blé de la façon suivante un grain dans la 1ère case, deux grains dans la 2ème case, ainsi de suite en doublant jusqu'à la 64e case Combien de grains de blé il y a dans la 64e case?
Answered by Claude Tardif.



Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.



Home Resource Room Home Resource Room Quandaries and Queries Mathematics with a Human Face About Math Central Problem of the Month Math Beyond School Outreach Activities Teacher's Bulletin Board Canadian Mathematical Society University of Regina PIMS