Pipe fills in a hours, with a leak in b hours: time for the leak to empty the tank

The same question, asked 3 times: 24 Jul 2023 S2*, 9 Sep 2024 S3*, 11 Sep 2024 S2. Every wording below, oldest first.

Try each one first, then open its answer.

Question 1
24 Jul 2023 S2
67 $A pipe can fill a tank in 30 hours. Due to a leakage at the bottom, it is filled in 50 hours. How much time will the leakage take to empty the completely filled tank?$
Tap an option to check your answer.
Question 2
9 Sep 2024 S3
73 $A pipe can fill an overhead tank in 12 hours. But due to a leak at the bottom, it is filled in 18 hours. If the tank is full, how much time will the leak take to empty it?$
Tap an option to check your answer.
Question 3
11 Sep 2024 S2
74 $Pipe A usually fills a tank in 6 hours. But due to a leak at the bottom of the tank, it takes extra 2 hours to fill the tank. If the tank is full, then how much time will it take to get emptied due to the leak?$
Tap an option to check your answer.

Question 1