SOLUTION: Here is my problem 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 does it take all 3 of t

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Here is my problem 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 does it take all 3 of t      Log On


   



Question 177029: Here is my problem
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 does it take all 3 of them working together to mix 20 drinks/

Found 2 solutions by ankor@dixie-net.com, stanbon:
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 does it take all 3 of them working together to mix 20 drinks/
;
let t = time required to mix 20 drinks working together:
:
let the completed job = 1; (the mixing of 20 drinks)
;
t%2F5 + t%2F10 + t%2F15 = 1
mult eq by 30, results:
6t + 3t + 2t = 30
11t = 30
t = 30%2F11
t = 2.727 min or 2 + .727(60) = 2 min 43.6 sec
:
:
Check solution
2.727%2F5 + 2.727%2F10 + 2.727%2F15 =
.5454 + .2727 + .1818 = .9999 ~ 1
;
SORRY ABOUT THE SCREW-UP HERE

Answer by stanbon(75887) 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 does it take all 3 of them working together to mix 20 drinks/
---------------------------------
Steven rate = 20/5 = 4 drinks/min
Sue rate = 20/10 = 2 drinks/min
Jack rate = 20/15 = (1.333..)drinks/min
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Combined rate : (4+2+1.333) = (7.333..)drinks/min
-----------------
Time to mix 20 drinks:
Convert to 20 drinks/x min
(20/7.333..)drinks / (20/7.333..)min = 20drinks/2.72 min
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Cheers,
Stan H.