Question

One pipe can fill a pool 1.25 times faster than a second pipe. When both pipes are opened, they fill the pool in five hours. How long would it take to fill the pool if only the slower pipe is used?

Answer 1

5(x+1.25x)=a; where x is speed(litres per hour) of slower pipe and a is a volume of pool(liters)

x+1.25x=a/5

2.25x=a/5

x=a/11.25

11.25x=a; what means that slower pipe need 11.25 hours (11 hours 15 minutes) to fill the pool

Answer: 11 hours 15 minutes