Question 596494: If Steven can mix 20 drinks in 5 minutes, Sue can mix 20 drinks in 10 minutes, and Jack can mix 20 drinks in 15 minutes, how much time will it take all 3 of them working together to mix the 20 drinks? Please show formula. thank you!
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! If Steven can mix 20 drinks in 5 minutes, Sue can mix 20 drinks in 10 minutes, and Jack can mix 20 drinks in 15 minutes, how much time will it take all 3 of them working together to mix the 20 drinks? Please show formula. thank you!
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Steve rate = (1/5) job/min
Sue rate = 1/10 job/min
Jack rate = 1/15 job/min
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Together rate = 1/x job/min
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Equation:
rate + rate + rate = together rate
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1/5 + 1/10 + 1/15 = 1/x
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Multiply thru by 30x to get:
6x + 3x + 2x = 30
11x = 30
x = 30/11 = 2 8/11 minutes (time to do the job together)
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