A road crew can repave 1/15 miles of road each hour. They must repave a road that is 3/5 miles long. How long will it take the crew to repave the road?

Question

A road crew can repave 1/15 miles of road each hour. They must repave a road that is 3/5 miles long. How long will it take the crew to repave the road?

Answer 1

Let's say the crew could do 2 miles per hour and they needed to do 10 miles.  We would take 10 and divide it by 2 and see that it would take them 5 hours.  This is the same thing, only it involves fractions, and to divide by a fraction you must multiply by its reciprocal.

 

3/5 ÷ 1/15 = 3/5 x 15/1 = 45/5 = 9 hours