Question

Deisha can build a fence in 15 hours, and Travis can build a fence in 12 hours. How long will it take them together to build a fence?

Answer 1

6
`(2)/(3)`

Explanation:

Deisha's build rate = 1 fence per 15 hours = 1/15 fences per hour

Travis's build rate = 1 fence per 12 hours = 1/12 fences per hour

Working together, their combined rate is 1/15 + 1/12 = 3/20 fences per hour

So it takes them 20/3 = 6 2/3 hours per fence