q: The no. of girls in a class are seven times the no. of boys, which value cannever be the of total students?
Options:
(A) 2
(B) 5
(C) 8
(D) 9
(E) 10
a: Stream of consciousness: Let the boys are X, then girls are 7X, total = X+7X = 8X
So it should be multiple of 8, 30 is not a multiple of 8. The answer is (C).

question: How many seconds will a train 140 meters long take to cross a bridge 150 meters long if the speed of the train is 36 kmph?
Options:
(A) 28 sec
(B) 29 sec
(C) 24 sec
(D) 25 sec
(E) 26 sec
answer: Stream of consciousness: D = 140 + 150 = 290
S = 36 * 5/18 = 10 mps
T = 290/10 = 29 sec The answer is (B).

q: Find the invalid no.from the following series 13, 18, 25, 30, 37, 40
Options:
(A) 23
(B) 25
(C) 40
(D) 46
(E) 48
a: Stream of consciousness: The differences between two successive terms from the beginning are 7, 5, 7, 5, 7, 5. So, 40 is wrong. The answer is (C).

question: The speed of a boat in still water is 40kmph and the speed of the current is 20kmph. Find the speed downstream and upstream?
Options:
(A) kmph
(B) kmph
(C) kmph
(D) kmph
(E) kmph
answer: Stream of consciousness: Speed downstream = 40 + 20 = 60 kmph
Speed upstream = 40 - 20 = 20 kmph The answer is (B).

q: A can do a piece of work in 4 hours; B and C together can do it in 3 hours, which A and C together can do it in 2 hours. How long will B alone take to do it?
Options:
(A) 1/19
(B) 1/11
(C) 1/12
(D) 1/17
(E) 1/14
a: Stream of consciousness: A's 1 hour work = 1/4;
(B + C)'s 1 hour work = 1/3;
(A + C)'s 1 hour work = 1/2
(A + B + C)'s 1 hour work = (1/4 + 1/3) = 7/12
B's 1 hour work = (7/12 + 1/2) = 1/12
B alone will take 12 hours to do the work. The answer is (C).

q: The average age of 11 boys is 50, if the average age of first six boys is 49 and that of the last six is 52. Find the boy age?
Options:
(A) 48
(B) 50
(C) 56
(D) 62
(E) 64
a:
Stream of consciousness: 1 to 11 = 11 * 50 = 550
1 to 6 = 6 * 49 = 294
6 to 11 = 6 * 52 = 312
6th = 294 + 312 550 = 56 The answer is (C).