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Question 157157: Jack usually mows his lawn in 6 hours. Marilyn can mow the same yard in 7 hours. How much time would it take for them to mow the lawn together. (simplify your answerr. Type an integer, proper fraction or mixed number)
Answer by ptaylor(2198)   (Show Source):
You can put this solution on YOUR website!
Let x=amount of time it takes them both working together to mow the yard
Jack mows at the rate of 1/6 yard per hour
Marilyn mows at the rate of 1/7 yard per hour
Together they mow at the rate of 1/6 +1/7 or 7/42 + 6/42=13/42 yard per hour
So, our equation to solve is:
(13/42)*x=1 (1 yard, that is) multiply each side by 42
13x=42 divide each side by 13
x=42/13 or 3 3/13 hour
CK
(1/6)(42/13)=7/13
(1/7)(42/13)=6/13
7/13 + 6/13=13/13 or 1 yard
Hope this helps---ptaylor
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