RRB NTPC CBT I 18 Jan 2021 Shift 1 Paper

© examsiri.com
Question : 3 of 100
 
Marks: +1, -0
Pipe A can fill a tank in 80 min and pipe B can fill the tank in 40 min. If A and B are opened together, then in how many minutes will the tank be filled?
Go to Question: