state gov UP Police Head Operator (Radio Cadre) Mock Test Quantitative Aptitude Time and Work Pipe and Cistern
A tanker is provided with two pipes X and Y. X can fill it in 20 minutes and Y can empty it in 30 minutes. If X and Y be kept open for one minute each, then how soon will the tanker be filled?
1
121 minutes
2
110 minutes
3
115 minutes
4
120 minutes