One water pipe fills a swimming bath in x hours. A second pipe takes 3 hours longer to fill the bath. The two pipes together fill the bath in two hours. How long will it take each pipe to fill the swimming bath separately?

2 Answers
Aug 13, 2018

I got 3 and 6 hours but check my maths anyway....

Explanation:

Have a look:

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Aug 13, 2018

First pipe takes 3 hours to fill the pool and second pipe takes 6 hours to fill the pool.

Explanation:

First water pipe takes x hours to fill swimming bath

hence, in one hour, it fills 1/x of the pool.

Second water pipe takes x+3 hours to fill swimming bath

hence, in one hour, it fills 1/(x+3) of the pool

In one hour they together fill 1/x+1/(x+3)=(2x+3)/(x^2+3x)

as it should fill half of the pool, we have

(2x+3)/(x^2+3x)=1/2

or x^2+3x=4x+6 i.e. x^2-x-6=0

i.e. (x-3)(x+2)=0 and x=3 or -2

As negative values are not permissible x=3

Hence first pipe takes 3 hours to fill the pool and second pipe takes 6 hours to fill the pool.