Two pipes are working to fill a tank...

Question

Two pipes are working to fill a tank. Together, they can fill the tank in 6 hours. If the larger pipe works twice as fast as the smaller pipe, how long would it take for each pipe to fill the tank if they worked separately?

Answer 1

This is a work problem which looks like this:

(1/x) + [1/(2x)] = 1/6.

After a little algebra the solution is x = 9 and 2x = 18 which means the faster pipe takes 9 hours and the slower one takes 18 hrs when working alone.

The reason for the equation is that the fractions are rates.