Pipe A can fill a tank in 5 hours, pipe B in 10 hours and pipe C in 30 hours. If all the pipes are open, in how many hours will the tank be filled?
Options:
(A) 5
(B) 4
(C) 3
(D) 6
(E) 8
Answer and stream of consciousness: (C)
Stream of consciousness: Part filled by A + B + C in 1 hour = 1/5 + 1/10 + 1/30 = 1/3
All the three pipes together will fill the tank in 3 hours.

Find the mean proportional between 81 & 100?
Options:
(A) A) 59
(B) B) 61
(C) C) 63
(D) D) 65
(E) E) 90
Answer and stream of consciousness: (E)
Stream of consciousness: Formula = ab
A = 81 and B = 100
81100 = 9 10 = 90

You are riding a horse. In front of you, there is a fire engine. A helicopter is following you. To your left a sports car is driving. To your right there is a depth.How can you arrange that you will all stop simultaneously, without crashing and without mutual communication?
Options:
(A) helicopter man stop it
(B) you stop it
(C) man go to stop it.
(D) no idea
(E) data irrelevant
Answer and stream of consciousness: (C)
Stream of consciousness: You ask the man of the merry-go-round to stop it.

The average of 13 numbers is 60. Average of the first 7 of them is 54 and that of the last 7 is 61. Find the 8th number?
Options:
(A) 25
(B) 83
(C) 45
(D) 53
(E) 64
Answer and stream of consciousness:
(A)
Stream of consciousness: Sum of all the 13 numbers = 13 * 60 = 780
Sum of the first 7 of them = 7 * 54 = 378
Sum of the last 7 of them = 7 * 61 = 427
So, the 8th number = 427 + 378 - 780 = 25.