SOLUTION: An aquarium tank can hold 7700 liters of water. There are two pipes that can be used to fill the tank. The first pipe alone can fill the tank in 44minutes. The second pipe can fill

Algebra ->  Rate-of-work-word-problems -> SOLUTION: An aquarium tank can hold 7700 liters of water. There are two pipes that can be used to fill the tank. The first pipe alone can fill the tank in 44minutes. The second pipe can fill      Log On


   



Question 178350: An aquarium tank can hold 7700 liters of water. There are two pipes that can be used to fill the tank. The first pipe alone can fill the tank in 44minutes. The second pipe can fill the tank in 77minutes by itself. When both pipes are working together, how long does it take them to fill the tank?
Found 2 solutions by ptaylor, Alan3354:
Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!
Let x=time needed for both tanks working together to fill the tank
Then together they fill at the rate of 7700/x gpm
First pipe fills at the rate of 7700/44=175 gpm
Second pipe fills at the rate of 7700/77=100 gpm
So, our equation to solve is:
175+100=7700/x multiply each term by x
175x+100x=7700 collect like terms
275x=7700 divide each side by 275
x=28 min-----------------time required to fill the tank when both pipes are working together.
CK
In 28 min, first pipe fills 28*175=4900 gal
In 28 min second pipe fills 28*100=2800 gal
4900+2800=7700
7700=7700
Does this help???---ptaylor

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
An aquarium tank can hold 7700 liters of water. There are two pipes that can be used to fill the tank. The first pipe alone can fill the tank in 44minutes. The second pipe can fill the tank in 77minutes by itself. When both pipes are working together, how long does it take them to fill the tank?
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A quick way to do these types of problems is:
product/sum
t = 77*44/(77+44)
t = 3388/121
t = 28
Saves minutes on a timed test.