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Question 301967: I know the answer to this problem, but I need help on how to actually find the answer. The problem is:
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?
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?
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Steven Data:
time = 5 minutes/job ; rate = 1/5 job/min
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Sue Data:
time = 10 min/job ; rate = 1/10 job/min
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Jack Data:
time = 15 min/job ; rate = 1/15 job/min
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Together Data:
time = x min/job ; rate = 1/x job/min
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Equation:
rate + rate + rate = together rate
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 = 2.73 minutes to mix 20 drinks
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Cheers,
Stan H.
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