Question 931706
Let t=time it takes newer pump to drain the pool
Newer pump drains at the rate of 1/t of the pool per hour
Older pump drains the pool in 5t hours
Older pump drains at the rate of 1/5t of the pool per hour
Our equation to solve is:
1/t + 1/5t =1/3  multiply each term by 15t
15+3=5t
5t=18
t=18/5=3.6  hours---time it takes newer pump to drain the pool

CK
1/3.6 + 1/18=1/3
5/18+1/18=1/3
1/3=1/3
Hope this helps---ptaylor