SOLUTION: Jack usually mows his lawn in 3 hours. Marilyn can mow the same lawn in 5 hours. How much time would it take for them to mow the lawn together?

Question 271639: Jack usually mows his lawn in 3 hours. Marilyn can mow the same lawn in 5 hours. How much time would it take for them to mow the lawn together?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Jack usually mows his lawn in 3 hours. Marilyn can mow the same lawn in 5 hours. How much time would it take for them to mow the lawn together?
JAck mows the lawn in 3 hours.
he does 1/3 of the job in 1 hour

Marilyn takes 5 hours . So she does 1/5th. job in 1 hour.
they together do 1/3 + 1/5 of the job in 1 hour.
= 8/15 of the job .
8/15 of the job they take 1 hour
so 1 job they take 15/8 hours
= 1.88 hours
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