<PRE><B>Question 170479</B>
Jack usually mows his lawn in 7 hours. Marilyn can mow the same yard in 4 hours. How much time would it take for them to mow the lawn together?
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Jack DATA:
Time = 7 hrs/job ; rate = 1/7 job/hr
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Marilyn = 4 hrs/job ; rate = 1/4 job/hr
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Together DATA:
Time = x hrs/job ; rate = 1/x job/hr
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EQUATION:
rate + rate = together rate
1/7 + 1/4 = 1/x
11/28 = 1/x
x = 28/11 = 2.545454... hrs
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Cheers,
Stan H.</PRE>