SOLUTION: Jack usually mows his lawn in 7 hours. Marilyn can mow the same yard in 5 hours. How much time would it take for them to mow the lawn together? The directions say "simplify you

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Question 376260: Jack usually mows his lawn in 7 hours. Marilyn can mow the same yard in 5 hours. How much time would it take for them to mow the lawn together?
The directions say "simplify your answer. type an integer, proper fraction, or mixed number."
Found 2 solutions by checkley79, Alan3354:
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
1/7+1/5=1/x
(5+7)/5*7=1/x
12/35=1/x
12x=35
x=35/12
x=2.92 hours ans.

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Use product/sum
7*5/(7+5) = 35/12 hours
= 2 hours 55 minutes