WBCS.LIVE practice question

There are 3 taps for filling water in a tank. The first tap takes 6 hours, the second tap takes 1 day and the third tap takes 18 hours to fill the tank. But there was a hole in the bottom, which was capable of draining a completely filled tank in 18 hours. The hole was discovered after 1 hour and was immediately repaired. How much time will it take to fill the tank from all three taps?

Solve this multiple-choice question and check the correct answer with its explanation below.