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?

Answer 1

Melissa’s speed = 1lawn/8hours

1/8 + x = 1lawn/5hours

1/5 - 1/8 =

8/40 - 5/40 = 3/40 = 1/13.3333333

Jing can mow 1 lawn in 13.3333333 hours.

1/13.333333 = r/1

Jing could mow 7.5% of the lawn in 1 hour.