A cistern normally takes 6 hours to be filled by a tap but because of a leak, 2 hours more. In how many hours will the leak empty a full cistern ?	Choose the most appropriate option:
A) 20 hours
B) 24 hours
C) 26 hours
D) 18 hours
E) None of these
∵ cistern fill in 6 hours.   ∴ in 1 hour, filled part = 1⁄6th   Now, due to leakage, filled part in 1 hour = 1⁄8th   Part of the cistern emptied, due to leakage in 1 hour   = 1⁄6 - 1⁄8 = 1⁄24th   ∴ The leakage will empty the full cistern in 24 hrs.   Answer 24 hours
<result>B</result>
A cistern normally takes 6 hours to be filled by a tap but because of a leak, 2 hours more. In how many hours will the leak empty a full cistern ?