An empty swimming pool can be filled to capacity through an inlet pipe in 3 hours, and it can be completely drained by a drainpipe in 6 hours . If both pipes are fully open at the same time , in how many hours will the empty pool be filled to capacity?

A 4
B 6
C 5
D 5.5

Correct Answer: 6

Inlet pipe fill 1/3 part of the pool in 1 hour Drain pipe drains 1/6 part of the pool in 1 hour So, together they fill (1/3 - 1/6 = 1/6) part of the pool in 1 hour So, together they will fill the pool completely in 6 hours [Shortcut : (Inlet×Outlet) / (Outlet - Inlet) = (3×6) / (6 - 3) = 6 hr]
Bissoy MCQ

Related Questions

Next steps