PQOTD 1/15/10

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?   (A) 2 minutes and 44 seconds   (B) 2 minutes and [...]