SOLUTION: Jack usually mows his own lawn in 7 hours. Marilyn can mow the same yard in 5 hours. How much time would it take them to mow it together???

Question 346108: Jack usually mows his own lawn in 7 hours. Marilyn can mow the same yard in 5 hours. How much time would it take them to mow it together???
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
Jack usually mows his own lawn in 7 hours. Marilyn can mow the same yard in 5 hours. How much time would it take them to mow it together???
.
Let x = time (hours) for both to mow it together
then
x(1/7 + 1/5) = 1
multiplying both sides by 35:
x(5 + 7) = 35
12x = 35
x = 35/12
x = 2.92 hours
or
x = 2 hours and 55 minutes
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