Question 262966

Let x=amount of time it takes all three, working together, to mix 20 drinks
Steve mixes at the rate of 4 drinks per min
Sue mixes at the rate of 2 drinks per min
Jack mixes at the rate of (4/3) drinks per min

Together, they mix at the rate of 4+2+(4/3) drinks per min=7 1/3=22/3 drinks per min

So, our equation to solve is:
(22/3)*x=20  multiply each side by 3
22x=60
x=2.73 min

CK
(2.73)*(7.33)=20
20.01~~~~20

Hope this helps---ptaylor