<PRE><B>Question 663482</B>
It takes Sarah 15 min to pick apples from the tree in her backyard. Lisa takes 25 min. How long will it take them working together?
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Sarah rate: 1/15 job/min
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Lisa rate: 1/25 job/min
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Together rate: 1/x job/min
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Equation:
rate + rate = together rate
1/15 + 1/25 = 1/x
25x + 15x = 15*25
40x = 15*25
x = (3/8)25 = 9 3/8 minutes (time to do the job together)
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Cheers,
Stan H.</PRE>