SOLUTION: two pipes are used to fill a water storage tank. the first pipe takes 12 hours to fill and the two together takes 1 hour less than it takes the 2nd pipe to to fill the tank alone.

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Question 317606: two pipes are used to fill a water storage tank. the first pipe takes 12 hours to fill and the two together takes 1 hour less than it takes the 2nd pipe to to fill the tank alone. how long will it take the 2nd pipe to fill the tank?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
1/12+1/x=1/(x-1)
1/12=1/(x-1)-1/x
1/12=(x-(x-1)/x(x-1)
1/12=-1/(x^2-x)
x^2-x=-12
x^2-x+12=0
(x-4)x+3)=0
x-4=0
x=4 hrs. for the second pipe to fill the tank working alone.
Proof:
1/12+1/4=1/(4-1)
1/12+1/4=1/3
1/12+3/12=1/3
4/12=1/3
1/3=1/3