Question

It takes Emily eight hours to paint her house. Mike can paint the same area in nine hours. Find how long it would take them if they worked together.

Group of answer choices

3.56 hours

7.58 hours

15.34 hours

4.24 hours

Answer 1

the answer would be 3.56

Answer 2

4.24 hours

Explanation:

It takes Emily eight hours to paint her house, then her unit rate is:

(1 house)/(8 hours) = 0.125 house/hour

Analogously, Mike unit rate is:

(1 house)/(9 hours) = 0.111 house/hour

If they work together their unit rates are added to get a combined unit rate as follows (units are omitted):

0.125 + 0.111 = 1/x

0.236 = 1/x

x = 4.24 hours