A cistern is normally filled in 6 hours but takes two hours longer to fill because of a leak in its bottom. If the cistern is full, the leak will empty it in? Select the correct option:
A) 33
B) 88
C) 24
D) 99
E) 11

Rationale: 1 / 6 - 1 / x = 1 / 8 x = 24 answer : c
Answer: C