Question

Bob can paint a fence in 12 hours, and working with Jen can paint a fence in 4 hours. How long would it have taken Jen to paint the fence alone?

Answer 1

6 hours

Explanation:

For Bob

12 hours = 1 fence

1 hour = 1/12 fence

Together Bob and Jen

4 hours = 1 fence

1 hour = 1/4 fence

Now, for Jen:

1 hour = 1/4 - 1/12= 3/12 - 1/12 = 2/12=1/6

Find the amount of time Jen will need:

1/6 fence = 1 hour

1 fence = 6 hour