2 pipes are used to fill pool. 1st pipe can fill the pool 6 hrs alone. two pipes can fill in 3 hrs less time than 2nd pipe. how long it will take for 2nd pipe

Question

please helpppppp me. i dont know how to solved it.

Answer 1

How much gets done per hour?

 

1/6 + 1/p = 1/(p - 3)

 

Once we find and apply the common denominator, 6p(p - 3), we only deal with the numerators.

 

p(p - 3) + 6(p - 3) = 6p

p² - 3p + 6p - 18 = 6p

p² - 3p - 18 = 0

(p - 6)(p + 3) = 0

 

p - 6 = 0

p = 6

 

p + 3 = 0

p = -3

Since we can't go back in time, we disregard this solution.

 

The 2nd pipe can also fill the pool in 6 hours alone.