Three pipes A, B and C can fill a cistern in 8 minutes,12 minutes and 16 minutes respectively. What is the time taken by three pipes to fill the cistern when they are opened together?

July 28, 2023

Question	Three pipes A, B and C can fill a cistern in 8 minutes,12 minutes and 16 minutes respectively. What is the time taken by three pipes to fill the cistern when they are opened together?
Type	multiple_choice
Option	3.7 minutes	correct
Option	4 minutes	incorrect
Option	4.5 minutes	incorrect
Option	5 minutes	incorrect

Solution :

Part of the tank filled by A in one minute = 1/8

Part of the tank filled by B in one minute = 1/12

Part of the tank filled by C in one minute = 1/16

Net part of the tank filled by A+B+C in one minute;

= 1/8 + 1/12 + 1/16

13/48 Part of the cistern is filled in one minute.

∴ The whole tank will be filled in 48/13 3.7 minutes