Question

Working together, Melissa and Jing can mow a lawn in 5 hours. It would take Melissa 8 hours to do the job alone.

What is the value of r, the part of the lawn that Jing could complete in 1 hour?

0.075
0.125
0.375
0.625

Answer 1

Let r = the fraction of the job Jin does per hour

Melissa does 1/8 of the job per hour

Together they do 1/5 of the job per hour

So

1/8 + r = 1/5

Answer 2

Solve for r