<PRE><B>Question 419350</B>
Jonathan can type a 20 page document in 40 minutes, susan can type it in 30 minutes, and Jack can type it in 24 minutes. Working together, how much time will it take them to type the same document?
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Jonathan rate: 1/40 job/min
Susan rate:: 1/30 job/min
Jack rate:: 1/24 job/min
Together rate:: 1/x job/min
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Equation:
rate + rate + rate = together rate
1/40 + 1/30 + 1/24 = 1/x
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Multiply thru by 120x to get:
3x + 4x + 5x = 120
12x = 120
x = 10 minutes (time for them to do the job together)
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Cheers,
Stan H.
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