question: Given a two-digit number, the unit's digit exceeds its ten's digit by 4 and the product of the given number and the sum of its digits is equal to 90, which of the options is the number?
Options:
(A) 26
(B) 15
(C) 37
(D) 62
(E) 73
answer: Stream of consciousness: Using the elimination method the option that fits this description is 15
5-1 = 4 (unit's digit that exceeds its ten's digit by 4)
15*6 = 90 (the product of the given number and the sum of its digits is equal to 175) The answer is (B).
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question: If six persons sit in a row, then the probability that three particular persons are always together is?
Options:
(A) 1/5
(B) 1/4
(C) 1/9
(D) 1/6
(E) 1/1
answer: Stream of consciousness: Six persons can be arranged in a row in 6! ways. Treat the three persons to sit together as one unit then there four persons and they can be arranged in 4! ways. Again three persons can be arranged among them selves in 3! ways. Favourable outcomes = 3!4! Required probability = 3!4!/6! = 1/5 The answer is (C).
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question: A train 210 meters long is running with a speed of 54 kmph. The time taken by it to cross a tunnel 120 meters long is?
Options:
(A) 29
(B) 22
(C) 48
(D) 99
(E) 11
answer: Stream of consciousness: D = 210 + 120 = 330
S = 54 * 5/18 = 15 mps
T = 330/15 = 22 sec The answer is (B).
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question: Find the value of y from given equation: (12)^3 x 6^4 432 = y?
Options:
(A) 2568
(B) 3468
(C) 4500
(D) 4876
(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).
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