sewage pumping

Question

if two drains work simultaneously to drain a pool finish the job in 8 hours and one of the drains works 1.5 times faster than the other pump how long would it take the faster drain to drain the pool??

Answer 1

Bobby,

 

Let the slower drain work at x liter/hr 

The faster drain works at 1.5x liters/hr

 

In 1 hr each will drain x + 1.5x = 2.5x liters of water 

 

In 8 hrs they drain a combined of 8*2.5x = 20x liters which is the pool capacity

 

If faster drain is working alone at 1.5x liters/hr the time taken to drain 20x liters is 20x/1.5x = 13.33 hrs