state gov UP Police Assistant Operator (Radio Cadre) Mock Test Quantitative Aptitude Time and Work Pipe and Cistern
Pipe P can fill \(\frac{3}{4}\) part of a tank in 18 hours and pipe Q can fill \(\frac{3}{5}\) part of the same tank in 12 hours. Both P and Q were kept open for 4 hours, then both were closed. Pipe R alone was then opened and it emptied the water in the tank in \(5\frac{1}{2}\) hours. Pipes P, Q and R together can fill the empty tank in:
1
30 hours
2
36 hours
3
35 hours
4
40 hours