question: Two pipes A and B can fill a cistern in 37 minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour, if the B is turned off after:
Options:
(A) 9
(B) 7
(C) 6
(D) 5
(E) 4
answer: Stream of consciousness: Let B be turned off after x minutes. Then, Part filled by (A + B) in x min. + Part filled by A in (30 -x) min. = 1. x(2/75 + 1/45) + (30 - x). 2/75 = 1 11x/225 + (60 - 2x)/75 = 1 11x + 180 - 6x = 225. x = 9. The answer is (A).

q: How much 60% of 50 is greater than 30% of 30?
Options:
(A) 21
(B) 91
(C) 11
(D) 17
(E) 12
a: Stream of consciousness: (60/100) * 50 (30/100) * 30
30 - 9 = 21 The answer is (A).

question: In a school of 850 boys, 34% of Muslims, 28% Hindus, 10% Sikhs and the remaining of other communities. How many belonged to the other communities?
Options:
(A) A) 125
(B) B) 627
(C) C) 153
(D) D) 238
(E) E) 159
answer: Stream of consciousness: 34 + 28 + 10 = 72%
100 72 = 28%
850 * 28/100 = 238 The answer is (D).

q: An archer is shooting arrows from various distances. She shoots at a target from 50 yards, 60 yards, and 70 yards. The probability that she hits within the bullseye from 50 yards is 3/4, the probability that she hits within the bullseye from 60 yards is 2/3, and the probability that she hits within the bullseye from 70 yards is 3/5. What is the probability that she hits the bullseye at least once in three shots, one from each distance listed.
Options:
(A) 9/10
(B) 14/15
(C) 19/20
(D) 29/30
(E) 39/40
a: Stream of consciousness: The probability that she hits the bullseye at least once = 1 - (the probability that she misses the bullseye every shot)
The probability that she misses every shot = (prob that she misses from 50 yards)*(prob that she misses from 60 yards)*(prob that she misses from 70 yards)
Prob that she misses from 50 yards = 1 - 3/4 = 1/4; Prob that she misses from 60 yards = 1 - 2/3 = 1/3; Prob that she misses from 70 yards = 1 - 3/5 = 2/5
Thus the probability that she misses all shots = (1/4)*(1/3)*(2/5) = 1/30
Thus the probability that she makes at least one shot = 1 - (1/30) = 29/30 The answer is (D).

question: There are two water tanks A and B, A is much smaller than B. While water fills at the rate of one liter every hour in A, it gets filled up like 10, 20, 40, 80, 160 in tank B. (At the end of first hour, B has 10 liters, second hour it has 20, third hour it has 40 and so on). If tank B is 1/32 filled after 21 hours, what is the total duration required to fill it completely?
Options:
(A) 22
(B) 28
(C) 269
(D) 26
(E) 82
answer: Stream of consciousness: The data related to the first tank A is not necessary. As you can see, the capacity that gets filled in the tank B after each hour is doubled. So If the tank is 1/32nd part is full after 21 hours, it is 1/16th part full after 22 hours, 1/8th part full after 23 hours, 1/4th part full after 24 hours, 1/2 full after 25 hours, completely full after 26 hours. The answer is (D).

question: Find the value of y from (12)^3 x 6^4 432 = y?
Options:
(A) 1234
(B) 2343
(C) 4546
(D) 3435
(E) 5184
answer:
Stream of consciousness: Given Exp. = (12)3 x 64 = (12)3 x 64 = (12)2 x 62 = (72)2 = 5184
432 12 x 62 The answer is (E).