q: X can finish a work in 21 days. Y can finish the same work in 15 days. Y worked for 5 days and left the job. how many days does X alone need to finish the remaining work?
Options:
(A) 12
(B) 13
(C) 16
(D) 14
(E) 18
a: Stream of consciousness: Work done by X in 1 day = 1/21
Work done by Y in 1 day = 1/15
Work done by Y in 5 days = 5/15 = 1/3
Remaining work = 1 1/3 = 2/3
Number of days in which X can finish the remaining work = (2/3) / (1/21) = 14 The answer is (D).

question: Three 6 faced dice are thrown together. The probability that exactly two dice show the same number on them is ?
Options:
(A) 5/16
(B) 5/12
(C) 5/87
(D) 5/56
(E) 5/38
answer: Stream of consciousness: Using question number 11 and 12, we get the probability as
1 - (1/36 + 5/9) = 5/12 The answer is (B).

q: Two persons A and B can complete a piece of work in 20 days and 40 days respectively. If they work together, what part of the work will be completed in 5 days?
Options:
(A) 1/8
(B) 1/3
(C) 3/6
(D) 3/8
(E) 5/3
a: Stream of consciousness: A's one day's work = 1/20
B's one day's work = 1/40
(A + B)'s one day's work = 1/20 + 1/40 = 3/40
The part of the work completed in 5 days = 5 (3/40) = 3/8. The answer is (D).

question: A train traveling at 72 kmph crosses a platform in 30 seconds and a man standing on the platform in 19 seconds. What is the length of the platform in meters?
Options:
(A) 220 meters
(B) 360 meters
(C) 420 meters
(D) 600 meters
(E) Cannot be determined
answer: Stream of consciousness: Speed of the train in metres/sec = 72000/3600 = 20
Distance travelled by train to cross the platform = 30 * 20 = 600 = Length of train + Length of platform
Distance travelled by train to cross the man = 19 * 20 = 380 = Length of train
Length of platform = 600 - 380 = 220 The answer is (A).

q: If Rs.7500 are borrowed at C.I at the rate of 4% per annum, then after 5 years the amount to be paid is?
Options:
(A) 3377
(B) 2688
(C) 2688
(D) 9125
(E) 1268
a: Stream of consciousness: A = 7500(26/25)^5 = 9125 The answer is (D).

q: It is the New Year and Mandy has made a resolution to lose weight this year. She plans to exercise and do yoga. For exercise she plans to workout at the gym and ride her bicycle in the ratio of 2:3 everyday. She will also do yoga in the ratio, yoga:exercise = 2:3. If she rides her bike for 10 minutes, how much time will she spend doing yoga? (rounded to minutes)
Options:
(A) 10 min.
(B) 41 min.
(C) 17 min.
(D) 23 min.
(E) 25 min.
a:
Stream of consciousness: The ratio is 2:3 = gym:ride, so (10)(3/2) = 15 minutes at the gym, and 15 + 10 = 25 minutes exercise, so (2/3)(25) = 17 minutes yoga. The answer is (C).