q: Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is?
Options:
(A) 299
(B) 2767
(C) 120
(D) 287
(E) 261
a: Stream of consciousness: Work done by the waste pipe in 1 minute = 1/15 - (1/20 + 1/24) = - 1/40
Volume of 1/40 part = 3 gallonsVolume of whole = 3 * 40 = 120 gallons. The answer is (C).

question: A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that all the four bulbs are defective.
Options:
(A) 62/63
(B) 125/126
(C) 1/63
(D) 1/42
(E) 1/126
answer: Stream of consciousness: Answer: Option E
Out of nine, five are good and four are defective. Required probability = c/c = 1/126 The answer is (E).

q: There are 6 fictions and 6 non-fictions. How many cases are there such that 2 fictions and 2 non-fictions are selected from them?
Options:
(A) 90
(B) 120
(C) 225
(D) 180
(E) 200
a: Stream of consciousness: Number of ways of selecting 2 fiction books = 6C2
Number of ways of selecting 2 non fiction books = 6C2
6C2 * 6C2 = 15 * 15 = 225 The answer is (C).

question: The edge of a cube is 5a cm. Find its surface?
Options:
(A) 150a2 cm2
(B) 170a2 cm2
(C) 125a2 cm2
(D) 175a2 cm2
(E) 120a2 cm2
answer: Stream of consciousness: 6a2 = 6 * 5a * 5a = 150a2 The answer is (A).

q: What will come in place of the x in the following Number series? 8, 10, 14, 22, 38, x
Options:
(A) 66
(B) 68
(C) 70
(D) 72
(E) 74
a: Stream of consciousness: 8
8 x 2 - 6 = 10
10 x 2 - 6 = 14
14 x 2 - 6 = 22
22 x 2 - 6 = 38
38 x 2 - 6 = 70 The answer is (C).

q: The length W of a rectangle is decreased by 15% and its width is increased by 40%. Does the area of the rectangle decrease or increase and by what percent?
Options:
(A) Decreases by 19%
(B) Decreases by 25%
(C) Increases by 6%
(D) Increases by 19%
(E) Increases by 25%
a:
Stream of consciousness: Let the length W of the rectangle be 100x, and width be 100y. Area = 100x * 100y = 10000xy
Now after the change Length = 85x, and width = 140 y. Area = 11900xy
% Change = (11900xy - 10000xy)/(10000xy) = 19 % Increase. Hence The answer is (D).