SOLUTION: Problem is from http://www.testprepreview.com/modules/algebra2.htm If Steven can mix 20 drinks in 5 minutes, Sue can mix 20 drinks in 10 minutes, and Jack can mix 20 drinks in

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Question 129873: Problem is from http://www.testprepreview.com/modules/algebra2.htm
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 edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
Steven can do 1/5 of the job in 1 minute, Sue 1/10 and Jack 1/15 in 1 minute.
Let j= the job.
1/5 + 1/10 + 1/15
6/30 + 3/30 + 2/30 = 11/30 of the job in 1 minute.
30/11= 2 8/11 minutes to mix 20 drinks together.
2 min 43.6 sec.
.
Ed