posted by anxious on .
Jack usually mows his lawn in 6 hours. Marilyn can mow the same lawn in 5 hours How much time would it take them to mow the lawn together?
In 30 hours, Jack mows 5 lawns, and Marilyn can mow 6 lawns.
That is 11 lawns in 30 hours.
so one lawn will take 30/11 hrs.
Jack's rate = job/6
Marilyn's rate = job/5
their combined rate = job/6 + job/5
job = rate x time
so time for combined effort = job/rate
So it takes 30/11 hours
= 2 8/11 hours