Problema Solution
Jack usually mows his lawn in 7 hours. Marilyn can mow the same lawn in 3 hours. How much time would it take for them to mow the lawn together?
Answer provided by our tutors
jack mows at an hourly rate of 1/7
marilyn mows at an hourly rate of 1/3
their combined hourly rate is 1/7+1/3 = 10/21
so for moving the lawn both will take time = 21/10 = 2.1 hours