railway RRB NTPC Mock Test Series 2024-25 (CBT 1 + CBT 2) Quantitative Aptitude Time and Work Pipe and Cistern
A tap can empty a tank in one hour. A second tap can empty it in 30 minutes. If both the taps operate simultaneously how much time is needed to empty the tank?
1
20 min.
2
30 min.
3
40 min.
4
45 min.