SSC CGL 10 Sep 2024 Shift 1 Paper

Question : 74 of 100

Marks: +1, -0

Three pipes P, Q and R can fill a cistern in 40 minutes, 80 minutes and 120 minutes, respectively. Initially, all the pipes are opened. After how much time (in minutes) should the pipes Q and R be turned off so that the cistern will be completely filled in just half an hour?