Working together, Jamie and Kit can build a wall in 4.5 hours. If Jamie can do the job in 6 hours working alone, how long would it take Kit to build the wall when working alone?

Answer 1

Working together: 1 wall in 4.5 hours = 9/2 hours

2/9 wall per hour

Jamie: 1 wall in 6 hours

1/6 wall per hour.

2/9 - 1/6 = 12/54 - 9/54 = 3/54 = 1/18

Kit will build the wall in 18 hours