Question

Working together, two pumps can drain a certain pool in 6 hours. If it takes the older pump 15 hours to drain the pool by itself, how pump to drain the pool on its own?

Answer 1

Answer:

10

Step-by-step explanation:

Rate of drainage for pump A and B = [1 pool drained]/[6 hours]

Rate of drainage for pump A (older pump) = [1 pool drained]/[15 hours]

Rate for pump B (newer pump) = [1 pool drained]/[t hours]

Thus, adding the rate of drainage of A and B,

1/t + 1/15 = 1/6

t=10