12 water pumps can make a water tank empty in 20 minutes. But 2 pumps are out of order. In how long will the remaining pumps take to make the tank empty?
12 water pumps can make a water tank empty in 20 minutes. But 2 pumps are out of order. In how long will the remaining pumps take to make the tank empty?
Past Papers:
PPSC Assistant (BS-16) — Past Paper MCQs
A: 20 minutes
B: 24 minutes
C: 28 minutes
D: None of these
Total pump-minutes = 12×20 = 240. With 10 pumps working; time = 240/10 = 24 minutes. Rate is proportional to number of pumps under equal efficiency.