Math & Logic · Ages 12–15
Riddle #156
One tap fills a bathtub in 6 minutes. A second tap fills the same tub in 3 minutes. With both running together, how long does the tub take to fill?
You solved this one before
Answer: 2 minutes
Add the rates, not the times: 1/6 + 1/3 = 1/2 of a tub per minute, so one full tub takes 2 minutes.