Give a quick stream of consciousness before answering the following question. Pipes A and B can fill a cistern in 8 and 24 minutes respectively. They are opened an alternate minutes. Find how many minutes, the cistern shall be full?
Options:
(A) 22
(B) 12
(C) 88
(D) 99
(E) 27
1/8 + 1/24 = 1/6
6 * 2 = 12
The answer: (B).