Q: A train running at the speed of 60 km/hr crosses a pole in 15 sec. What is the length of the train?
Options:
(A) 356
(B) 250
(C) 127
(D) 279
(E) 150
A: OK... Stream of consciousness: Speed = 60 * 5/18 = 50/3 m/sec
Length of the train = speed * time = 50/3 * 15 = 250 m
The answer is (B).

Q: If n is a natural number, then (6n^2 + 6n) is always divisible by
Options:
(A) 6 only
(B) 6 and 12 both
(C) 12 only
(D) 18 only
(E) 12 and 18 both
A: OK... Stream of consciousness: (6n^2 + 6n) = 6n(n + 1), which is divisible by both 6 and 12, since n(n+1) is always even.
The answer is (B).

Q: 10 people meet and shake hands. The maximum number of handshakes possible if there is to be no "cycle" of handshakes is (A cycle of handshakes is a sequence of k people a1, a2, , ak (k > 2) such that the pairs {a1, a2}, {a2, a3}, , {ak-1, ak}, {ak, a1} shake hands).
Options:
(A) 7
(B) 6
(C) 9
(D) 8
(E) 10
A: OK... Stream of consciousness: The question is not written in proper manner but we can work in 3 methods
1) If these are random handshakes, then total methods = 10*9/2*1 = 45
2) If these are cyclic handshakes, then total methods = 10
3) If these persons are not cyclic but they are arranged in a straight bench, then number of methods = 9
The answer is (C).

Q: An urn contains 6 red, 5 blue and 2 green marbles. If 2 marbles are picked at random, what is the probability that both are red?
Options:
(A) 6/13
(B) 5/26
(C) 6/26
(D) 9/26
(E) 10/27
A:
OK... Stream of consciousness: Option(B) is correct
P(Both are red), 6C2/13C2 = 5/26
The answer is (B).