<PRE><B>Question 166650</B>
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 togehter to mix the 20 drinks

Steven can mix 20 drinks in 5 minutes 
then Steven can mix 20/5 = 4 drinks per minute

Sue can mix 20 drinks in 10 minutes
then Sue can mix 20/10 = 2 drinks per minute

Jack can mix 20 drinks in 15 minutes
then Jack can mix 20/15 = 4/3 drinks per minute

So working together they can mix 4+2+4/3 drinks per minute
They do 22/3 drinks per minute

They do 20 drinks in 20/(22/3)=60/22= 30/11 minutes

Answer: they can mix 20, drinks in 30/11 minutes (2.72 minutes aprox)


</PRE>