engineering recuitment NIELIT Scientific Assistant Mock Test 2025 Quantitative Aptitude Time and Work Pipe and Cistern
Two inlet pipes, P1 and P2, can fill a cistern in 20 hours and 30 hours, respectively. They were opened at the same time, but pipe P1 had to be closed 5 hours before the cistern was full. How many hours in total did it take for the two pipes to fill the cistern?
1
15 hours
2
9 hours
3
12 hours
4
10 hours