Question

One pump can empty a pool in 6 days, whereas a second pump can empty the pool in 12 days. How long will it take the two pumps, working together, to empty the pool?

It will take the two pumps days to empty the pool together.

Answer 1

4 days

Explanation:

work of first pool in a day = 1/6

work of the second pool in a day = 1/12

if they work together

1/6 + 1/12 = (2+1)/12 = 3/12 in a day

3/12 · 4 = 12/12 (the entire work)

So it takes 4 days