







The price of a watermelon 
20180707 

From errin: the price of the watermelon is directly proportional to its weight. If a watermelon that weighs 22 pounds cost $5.40, how much will a 17.5 pound watermelon cost? Answered by Penny Nom. 





Water in a cone 
20180210 

From Shuvo: The diagram shows a vertical crosssection of a container in the form
of an inverted cone of height 60 cm and base radius 20 cm. The circular
base is held horizontal and uppermost. Water is pursed into the
container at a constant rate of 40 cm3/s.
Show that, when the depth of water in the container is x cm, the
volume of the water in the container is (πx^3)/27 cm3.
Find the rate of increase of "x" at the instant when "x" = 2. Answered by Penny Nom. 





Water leaking from a trough 
20161228 

From Kathryn: A trough is 6 m long, and has uniform crosssection of an equilateral triangle with sides 1 m.
Water leaks from the bottom of the trough, at a constant rate of 0.1 m3/min.
Find the rate at which the water level is falling when the water is 0.2m deep. Answered by Penny Nom. 





Travelling upstream and downstream 
20161017 

From Kathleen: It took a boat 2 hours to reach town A going upstream. The way back was 1h20 min. What is the speed of the boat in still water if the speed of the stream is 3 mph? Answered by Penny Nom. 





A graph of the water level of a river 
20160105 

From emoni: Suppose that the water level of a river is 34 feet and that it is receding at a rate of 0.5 foot per day. Answered by Penny Nom. 





Water in a spherical container 
20141017 

From Natalie: A spherical container with radius 10cm being filled with water such that the water level, h cm, in the container increase at a rate of 0.5 cm s^(1). Show that the area of the horizontal surface of water, A cm^(2), in the container is given by A = π(20h  h^(2) ). Answered by Penny Nom. 





Water usage in Ames 
20140829 

From Abigail: The City of Ames water treatment plant treats 7 million gallons of water per day on
average to meet water demands. Hypothetically, if water is withdrawn from a
groundwater system with an area of 51.6 square miles
(approximate area of Ames and surrounding area),
what is the depth of water in inches that would have to be added to
the groundwater system annually to replace the water that is withdrawn by the city? Answered by Penny Nom. 





Mixing water and wine 
20140119 

From manish: a man mixes three part of water to one part of wine.When he consumes
one part of mixture he realise that the drink is too dilute and hence adds one part of
wine to the remaining quantity what is the ratio of water to wine in the new mixture. Answered by Penny Nom. 





Cubic centimeters, milliliters and grams 
20130926 

From Laura: How do I find the volume of a cube with dimensions of .78 cm, .3 cm and .22 cm? Then find the volume in ML and the mass if filled with water? Answered by Penny Nom. 





Water use in a rectangular flush tank 
20130510 

From milo: A rectangular flush tank 22" by 71/4 contains water to depth of 17" how many gallons of water will be saved if a conservation device reduces the capacity to 3/5 of this amount? And reduced to the nearest tenth Answered by Penny Nom. 





The weight of a pipe full of water 
20130116 

From joe: how do you figure out the weight of a pipe full of water Answered by Harley Weston. 





A project on reclaiming water 
20121211 

From shannon: I'm doing a report to reclaim water off of our campus facility to store in a cistern to use to flush toilets.
In Southeast Wisconsin and average of 82 inches of rain and snow fall annually.
I want to collect that off of the roof of our school building.
The roof is 37128 square feet.
how many gallons annually could I collect? Answered by Penny Nom. 





A semicircular roof gutter 
20120409 

From Kyle: A semicircular roof guttering contains some water.
The crosssection of the guttering has a diameter of 10 centimetres. The surface of the water collected in the guttering is 8cm.
What is the depth of water in the gutter? Answered by Penny Nom. 





A water tank is in the shape of a truncated cone 
20120308 

From Victoria: Suppose you have a water tank in the shape of a truncated cone. The larger diameter is K, the smaller diameter is K/2, and the height is also K (all measured in meters). The force of gravity on an object of mass, m, is F=9.8m (measured in Newtons). The density of the water is 1000 kilograms per cubic meter. What is the volume of the tank and how much mass will the tank have when it is full? Answered by Penny Nom. 





A hemispherical bowl with a lead ball inside 
20110927 

From Jean: "(a) Water is being poured into a hemispherical bowl of radius 3 inch
at the rate of 1 inch^3/s. How fast is the water level rising when the
water is 1 inch deep ?
(b) In (a), suppose that the bowl contains a lead ball 2 inch in
diameter, and find how fast the water level is rising when the ball is
half submerged." Answered by Penny Nom. 





A trough of water 
20110501 

From alvin: A trough is formed by nailing together, edge to edge, two boards 11 ft. in length, so that the right section is a right triangle. If a 15 gallon of water are poured into the trough and if the trough is held level so that a right section of water is an isosceles right triangle, how deep is the water? (231cu.in=1 gal.) Answered by Penny Nom. 





A fence around a water tank 
20110201 

From Heath: I am building a fence around a water tank. the fence is to be in the shape of a normal octagon. The tank has a circumference of 57 ' 6''. I would like the fence to be 3 ft from the tank at the skinny point . How would I calculate(for the simple guy) where to set each of my 4x4 posts at the 8 corners. Any help would be greatly appreciated. Answered by Harley Weston. 





A water trough 
20101022 

From Jasmine: A water trough is 8 m long and its crosssection is an isosceles
trapezoid which is 90 cm wide at the bottom and 120 cm wide
at the top, and the height is 30 cm. The trough is not full.
Give an expression for V , the volume of water in the trough in cm^3,
when the depth of the water is d cm. Answered by Stephen La Rocque. 





How many cubic metres of water can safely be stored in the tank? 
20100910 

From susanna: This water tank is a perfect sphere with an inner radius of 12 metres. However, they used inferior materials to build the water tank, and the tank can only withstand a water pressure of 185 kiloPascals. Assume the density of water is exactly 1000 kg/m3, gravity is 9.8 metres/s2, and disregard atmospheric pressure.
How many cubic metres of water can safely be stored in the tank? Round DOWN to the nearest whole number (since rounding up could be catastrophic in this instance!), and please submit only a number with no other information. Answered by Robert Dawson. 





The number of gallons of water in a basement 
20100523 

From George: A basement with dimensions 68 ft long by 42 ft wide by 10 ft deep is flooded to the ceiling calculate the number of gallons of water in the basement. 70 Answered by Penny Nom. 





A trough of water 
20090915 

From Darrell: A trough that measures 4 feet long, 22 inches wide, and 18 inches high will be mounted
on a support stand. If the trough weighs 50 pounds when empty, approximately how many
pounds must the stand be able to hold when the trough is full of water? Answered by Penny Nom. 





The volume of water in a cone 
20090317 

From Freddie: A ball of diameter 20cm rests in a conical container whose angle with the slant height and the vertical axis is 25degrees. if water is poured into the container just enough to touch the bottom of the ball, find the quantity of water in the container. Answered by Penny Nom. 





The weight of water in a swimming pool 
20090310 

From ely: How much does the water in a swimming pool 20 ft long, 10 ft wide, and 6 ft deep weigh? Answered by Penny Nom. 





Mixing watercolour paints 
20080907 

From bob: So, I'm making a chart to help me mix watercolor paints. There are
25 different paints. Each paint will mix with another paint just 1 time.
There is no need to mix red with blue, and then blue with red. Since
the result is the same, we only need 1 combination of the 2 paints.
And there is no need to mix red with red, so we can eliminate 25
combinations of the same paint. Answered by Penny Nom. 





A water acid mixture 
20080819 

From Sulagna: A chemical solution is made by mixing an acid with water in the ratio 1:24.
This solution is then taken and mixed with water in the ratio 1:3. How much acid
would be there in 200ml of this final solution? Answered by Penny Nom. 





A cubic mile of water 
20080803 

From Fred: [QQ] HOW MUCH WATER IS THERE IN A CUBIC MILE? Answered by Stephen La Rocque. 





The rate of change in the depth of the water 
20080612 

From Liz: A rectangular pool 50ft long and 30ft. wide has a depth of 8 ft. for the first 20 ft. for its length and a depth of 3 ft. on the last 20ft. of its length and tapers linearly for the 10 ft in the middle of its length. the pool is being filled with water at the rate of 3ftcubed/ min
at what rate is the depth of the water in the pool increasing after 15 hours? Answered by Harley Weston. 





The volume of a stone 
20080417 

From sara: a rectangular tank 30 cm long and 20 cm wide is filled with water to a depth of 8 cm. When a stone was put in, the water level rose to 11 cm. Find the volume of the stone. (Assume that the stone is completely under water.) Answered by Penny Nom. 





The amount of water in a pool 
20080330 

From anurag: what will the weight of water in a swimming pool having dimensions of 18ft *10ft*5 ft?
how much water will be needed for filling it up? Answered by Penny Nom. 





How much does water weigh per gallon? 
20080218 

From sofie: how much does water weigh per gallon Answered by Penny Nom. 





The volume of a tank 
20080127 

From Fred: A cubic tank holds 1,000 kilograms of water what are the dimensions of the tank in meters? Answered by Harley Weston. 





Related Rates (a water trough) 
20071107 

From Christina: A rectangular trough is 3ft long , 2ft across the top and 4 ft deep. If water flows in at the rate of 2ft^3/min, how fast is the surface rising when the water is 1 ft deep ? Answered by Stephen La Rocque. 





Can you tell me how many gallons it holds? 
20070925 

From Jeff: Hi my water tank is 10ft long and 45" around,can you tell me how many
gallons it holds.thankyou jeff Answered by Penny Nom. 





1 foot of snow = how much rain 
20070925 

From Lisa: 1foot of snow = how much rain Answered by Penny Nom. 





How much water is this? 
20070816 

From Judy: Have an area 731 sq. ft with 5" of water all the way around. How many gallons is this? Your help is appreciated. Answered by Stephen La Rocque. 





Water bill woes 
20070812 

From Terry: I know that a cubic foot of water=7.48051945 gals., but I keep getting my water bill and they go by thousands of a gal. per cubic foot. Is there a conversion that says that shows this? Water department=.763 x cubic foot used=thousands of gallons water used that month. Exampel: 72cu. ft meter reading x .763+ 58. galons of water I use in a month. Total 58=thousand = +gallons. This is wrong. There are only two people in the house. Answered by Stephen La Rocque. 





Comparing flow rates of two pipes 
20070714 

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. 





Dried grapes and percentage of water content 
20070709 

From Jyoti: Fresh grapes contain 90% water by weight while dried grapes contain 20 % water by weight. what will be the weight of dry graprs available from 20kg of fresh grapes? Answered by Stephen La Rocque. 





I need to provide 712 cubic feet to water storage capacity 
20070703 

From William: I need to provide 712 cubic feet to water storage capacity.
If I use 15 inch diameter pipe, what would the length need to be
to provide the capacity? Answered by Stephen La Rocque. 





Water tank volume 
20070529 

From Cecelia: I HAVE A SEMI CIRCULAR TANK AGAINST A WALL MEASURING 6'10" ACROSS THE WIDEST PART AND 3' FROM THE WALL TO THE FRONT OF THE TANK. THE DEPTH IS 14". PLEASE HELP ME TO CALCULATE THE VOLUME OF WATER IN THE TANK. Answered by Stephen La Rocque. 





Converting mass and volume of water 
20070510 

From Shian: Hello please help, I just can't seem to get the convertion thing and my mom tried to help but I still don't get it. How many grams does 1 milliliter of water weight? I was told 1g. How many grams does 0.1 liter of water weight? I was told 0.1g. Can you tell me if the answers given are correct with an explaination that I can understand? Thank you. Answered by Stephen La Rocque. 





Calculating rainwater volume 
20061230 

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. 





3.253 cubic meters of water 
20061031 

From Elaine: a tank full of water that has a volume of 3.253 cubic meters would have a mass of? Answered by Penny Nom. 





How fast is the water level rising when the water is 1 meter deep? 
20061019 

From Don: The cross section of a 5meter trough is an isosceles trapezoid with a 2meter lower base, a 3meter upper base and an altitude of 2 meters. Water is running into the trough at a rate of 1 cubic meter per minute. How fast is the water level rising when the water is 1 meter deep? Answered by Stephen La Rocque. 





How much water it will hold? 
20060920 

From Doug: I have thirty feet of piping that is two inches in diameter and I want to know how much water it will hold and the equation for solving the answer. Answered by Stephen La Rocque. 





Litres of water in my swimming pool 
20060816 

From A student: I need to calculate how many litres in my swiming pool, it is a circle shape, 5.5 m in diametre by 1.07 m deep. Answered by Stephen La Rocque. 





Gallons of water in a well 
20060731 

From Martha: I have a shallow water well that is 30 feet in depth.
I have 8 feet of water in the well.
The water well is a 30 inch in diameter.
My question : How many gallons of water is in my tank? Answered by Penny Nom. 





Ounces of water to grams 
20060716 

From Liza: How many grams is in 10 ounces? I'm asking this question because i just bought a sea monkey and it says add 10 ounces of water and I don't know what that means. I have asked my parents but neither of them know. Answered by Stephen La Rocque. 





Two water jugs 
20060705 

From Kisha: suppose that you have two water jugs, one which holds three gallons and one which holds five gallons. in additions, you have a water faucet at your disposal. your job is to find a method that produces exactly one gallon of water, another method that produces exactly two gallons of water, another method that produces exactly three etc up to exactly eight gallons of water. you may fill jugs from the faucet or from one another. you may not rough estimates??? Answered by Penny Nom. 





The volume of water in a sphere shaped water tower 
20060514 

From Dan: I work in the water industry, providing automatic controls for water systems. I was wondering if there was a formula for calculating the volume of water in a sphere shaped water tower? With the use of a pressure gauge we know the elevation of zero water {the bottom of sphere) and the overflow elev. (near the top of sphere) I would like to calculate how many gallons are at any elevation in between. Answered by Stephen La Rocque. 





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. 





How much does 1300cc of liquid weigh? 
20060428 

From Debra: How much does 1300cc of liquid weigh, and how is the formula equated? Answered by Stephen La Rocque. 





The waterway between Lake Huron and Lake Superior 
20060321 

From Trenae: the waterway between lake huron and lake superior separates the u.s and canada.it is usually 13 feet above the water when its closed and each section is 210 feet long if the angle of elevation is 70 degrees then what is the distance from the top of the drawbridge to the water and the width of the gap created by the 2 sections of the bridge Answered by Penny Nom. 





If an acre of land is covered with one inch of water 
20051227 

From Patti: If an acre of land (43560 sq ft) is covered with one inch of water, how many gallons of water cover that acre. Answered by Penny Nom. 





Two water jugs 
20040816 

From A student: You go to a source of water with two jugs and only two jugs. One jug has a capacity of exactly three pints and the other five pints. Both jugs are opaque (you can`t see inside them) and irregularly shaped. You have no other water containers. You do not have a scale. How can you use the two jugs and only the two jugs to measure exactly four pints of water? Answered by Penny Nom. 





Water in a pipe 
20040425 

From Marlean: How much water would be in a 480 foot one inch inside diameter pipe?? In imperial gallons please. thanking you in advance for your help in this matter.
Answered by Penny Nom. 





A water lily 
20040317 

From Inba: A water lily with a rigid stem extends one foot above the surface of the water. When pulled over, it disappears beneath the water at a distance 3 feet from where the stem originally entered the water. How deep is the pond? Answered by Penny Nom. 





Three jugs 
20040226 

From Shelly: You have three jugs: A 6 Liter, 4 Liter and a 3 Liter. Your goal is to get exactly 5 Liters of liquid in the 6 Liter jug. Your supply of liquid is unlimited and there are NO markings on the containers. You cannot do halves. Answered by Claude Tardif. 





A fish tank 
20031126 

From Bill: How do I work out the volume and weight of water in a fish tank that is 36in x 14in x 12in? Answered by Penny Nom. 





Water in a tank 
20030902 

From A parent: if a tank is 48 inches long 14 inches wide and 18 inches deep if a yardstick was inserted into the tank and measured 2 inches of water in the tank how many gallons of water would be in the tank. Answered by Penny Nom. 





Water in a cone 
20030812 

From Adrienne:
Water is poured into a tank in the shape of an inverted right circular cone.ð The height of the tank is 8 m and its radius at the top is 4 m. a. Draw and label a picture to represent this situation.ð (I know how to do this) b. Identify all variable quantities. (h = 8m, r = 4m) c. Find an equation that relates the variable quantities, and reduce the number of variable quantities to two. I was thinking about the equation V = 1/3 pi r^{2} h, which is the Volume of a cone, but I am stumped as to how I am supposed to "reduce the number of variable quantities to two." Can you point me in the right direction? Answered by Penny Nom. 





Two tanks of water 
20021108 

From A student: A 2000 L tank containing 550 L of water is being filled with water at the rate of 75 L per minute from a full 1600 L tank. How long will it be before the two tanks have the same amount of water? Answered by Penny Nom. 





Two rate problems 
20020930 

From Rebecca:
 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?
 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. 





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. 





Water jars 
20010827 

From Pe3te: Stacie and Kacie each have a jar. Stacies jar holds 5 quarts of water and Kacies jar holds 3 quarts. The girls dad ask them to go get him some water from the pump and to get him 1 gallon of water (NO MORE NO LESS) The jars were not marked in any way. In ten minutes the girls where back with 1 gallon. How did they get exactly 1 gallon ? 1) there are two ways to do it I only no one. 1st answer is..... Answered by Penny Nom. 





Connecting to a water line 
20001020 

From Vanja: My question is...A house is to be connected to a new water main that runs along the line y=2/3x1. The connection point at the house has coordinates (2,9), where the units represent metres. What lenght of plastic pipe is needed to connect to the water main at the closest point? Answered by Penny Nom. 





A trig question 
20000701 

From Will: An open rectangular tank a units deep and b units wide holds water and is tilted so that the base BC makes an angle theta with the horizontal. When BC is returned to the horizontal, who that the depth of the water is (a squared) * cot theta div 2b units Answered by Harley Weston. 





The weight of a watermelon 
20000425 

From Lori Speir: If I have a 100 pound watermelon and it is 99% water. If it sits out in the sun all day and is now only 98% water what does it weigh now? Answered by Penny Nom. 

