Correct option is D
Given:
Time taken by tap to fill the tank = 16 hours
Time taken to fill tank with hole = 24 hours
Concept Used:
The rate of work of each person is the reciprocal of the time they take to complete the work. example,
A complete work in x day,
Rate of work in one day = day
Solution:
Let the hole alone empty the full tank in x hours.
Combined work = Tap's work − Hole's work.
x = 48
So, The hole alone can empty the full tank in 48 hours.
Thus, the correct answer is (d).
Alternative Method:

Time = hours