SOLUTION: 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 t

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Question 315378: 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 20 drinks?
Answer by ankor@dixie-net.com(22740) About Me  (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 20 drinks?
:
let t = time required when they all worked together
:
Let the completed job = 1 (the mixing of 20 drinks)
:
t%2F5 + t%2F10 + t%2F15 = 1
Multiply by 30, results
6t + 3t + 2t = 30
:
11t = 30
t = 30%2F11
t = 2.73 minutes, or 2 min 44 sec
:
:
Check solution using a calc
2.73%2F5 + 2.73%2F10 + 2.73%2F15 =
.546 + .273 + .182 = 1.00