Of two garden taps, one fills a water barrel in 7 hours and the other in 21 hours. With both taps running, how many hours does the barrel take to fill?

Question

Accepted Answer

5.25. Combined rate = 1/7 + 1/21 = 3/21 + 1/21 = 4/21 of the barrel per hour, so time = 21/4 = 5.25 hours.

Of two garden taps, one fills a water barrel in 7 hours and the other in 21 hours. With both taps running, how many hours does the barrel take to fill?

Step-by-Step Solution

Master this topic in 30 minutes a day.

More Time & Work / Pipes practice