SOLUTION: I am having difficulty with this word problems, I am not sure where to begin. If Steve can mix 20 drinks in 5 minutes, Sue can mix 20 drinks in 10 minutes, Jack can mix 20 drink

Click here to see ALL problems on Mixture Word Problems

Question 151255: I am having difficulty with this word problems, I am not sure where to begin.
If Steve can mix 20 drinks in 5 minutes, Sue can mix 20 drinks in 10 minutes, Jack can mix 20 drinks in 15 minutes, how much tie will it take if all 3 of them work together to mix 20 drinks?
The study guide lists the answer as 2 minutes, 44 seconds
Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
If Steve can mix 20 drinks in 5 minutes, Sue can mix 20 drinks in 10 minutes, Jack can mix 20 drinks in 15 minutes, how much tie will it take if all 3 of them work together to mix 20 drinks?
:
Here's an easy way to do this:
:
Let t = time required when they all work together
Let the completed job = 1 (the mixing of 20 drinks)
:
+ + = 1
Multiply equation by 30 to get rid of the denominator:
:
6t + 3t + 2t = 30
:
11t = 30
t =
t = 2.727 hrs. Change the decimal hrs to minutes: .727 * 60 = 43.6 min
or
t = 2 min 44 sec