q: A train 250 m long is running at a speed of 27 km/hr. In what time will it pass a bridge 200 m long?
Options:
(A) 40
(B) 45
(C) 50
(D) 55
(E) 60
a: Stream of consciousness: Speed = 27 * 5/18 = 15/2 m/sec
Total distance covered = 250 + 200 = 450 m
Required time = 450 * 2/15 = 60 sec The answer is (E).

question: Find the average of the first 25 natural numbers?
Options:
(A) 8
(B) 9
(C) 13
(D) 11
(E) 12
answer: Stream of consciousness: Average of the first 'n' natural numbers = (n + 1)/2
We get (25 + 1)/2 = 13 The answer is (C).

q: If the ratio of boys to girls in a class is B and the ratio of girls to boys is G; then 10(B + G) is ?
Options:
(A) Equal to 3
(B) Less than 3
(C) More than 10
(D) Less than 10
(E) none of these
a: Stream of consciousness: Let number of boys = x
Let number of girls = y
Therefore x/y = B and y/x = G
10(B + G) = 10[(x/y) + (y/x)] = 10[(x2 + y2)/xy] > 10 The answer is (C).

question: If a man can cover 30 metres in one second, how many kilometres can he cover in 3 hours 45 minutes?
Options:
(A) 118 km
(B) 162 km
(C) 1767 km
(D) 1887 km
(E) 405 km
answer: Stream of consciousness: 30 m/s = 30 * 18/5 kmph
3 hours 45 minutes = 3 3/4 hours = 15/4 hours
Distance = speed * time = 30 * 18/5 * 15/4 km = 405 km. The answer is (E).

q: At 15:00 there were 22 students in the computer lab. At 15:03 and every three minutes after that, 3 students entered the lab. If at 15:10 and every ten minutes after that 8 students left the lab, how many students were in the computer lab at 15:44 ?
Options:
(A) 7
(B) 14
(C) 25
(D) 27
(E) 32
a: Stream of consciousness: Initial no of students + 3 * (1 + No of possible 3 minute intervals between 15:03 and 15:44) -
8 *(1 + No of possible 10 minute intervals between 15:10 and 15:44)
20 + 3*14 -8 * 4 = 32 The answer is (E).

q: A man sells two articles for Rs.3600 each and he gains 30% on the first and loses 30% on the next. Find his total gain or loss?
Options:
(A) 9 % loss
(B) 10% gain
(C) 450
(D) 12% loss
(E) 12% gain
a:
Stream of consciousness: (30*30)/100 = 9%loss The answer is (A).