Question

Next-door neighbors Bob and Jim use hoses from both houses to fill Bob's swimming pool. They know that it takes 24 h using both hoses. They also know that Bob's hose, used alone, takes 20% less time than Jim's hose alone. How much time is required to fill the pool by each hose alone?

Answer 1

use fractions of the pool that it takes to fill in 1 hour
for the 2 hoses this is 1/24 of the pool
let fraction for jims be 1 /t then for Bob this will be 0.8t

so we have the equation
1/t + 1/0.8t = 1/24

solve for t

Answer 2

multiply through by 25t:-

24 + 30 = t

now its easy

Answer 3

* by 24t