Question

A pool can be filled by one pipe in 8 hours and by a second pipe in 2 hours. How long will it take using both pipes to fill the​ pool?

Answer 1

let the time taken to be filled by both pipes be y

1/2 +1/8=1/y

(4+1)/8=1/y

5/8=y

cross multiplying

5y=8

y=8/5

=1.6hrs