Question

A cistern can be filled by one tap in 4 hours and another tap in 6 hours . How long will it take to fill the cistern if both tap are opened together ?​

Answer 1

Answer:

A cistern can be filled by one tap = 4 hours

There four part of the cistern filled by the tap in 1 hours = 1 by 4

Cistern can be filled by another tap = 6 hours

There four part of the cistern filled by the tap in 1 hours = 1 by 6

Part of the cistern can be filled by both the tap = 1 by 4 + 1 by 6

Full cistern can be filled by both the tap = 12 by 5 = 2, 2 by 5