My bath has two taps and a plug hole. The cold tap on its own fills the bath in 15 minutes, the hot one in 6 minutes. The plug hole can drain the bath in 30 minutes with the taps off. How long will the bath take to fill if I leave both taps on with the plug left out?
Answer
5 minutes
1/15(Cold) + 1/6(Hot) = 1/x + 1/30
solve for x.
1/5 = 1/x =======> 5 minutes
