q: If six persons sit in a row, then the probability that three particular persons are always together is ?
Options:
(A) 1/3
(B) 1/9
(C) 1/5
(D) 1/7
(E) 1/1
a: 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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q: What is the are of an equilateral triangle of side 12 cm?
Options:
(A) 36âˆš3 cm2
(B) 74âˆš3 cm2
(C) 64âˆš3 cm2
(D) 64âˆš5 cm2
(E) 14âˆš3 cm2
a: Area of an equilateral triangle = âˆš3/4 S2
If S = 12, Area of triangle = âˆš3/4 * 12 * 12 = 36âˆš3 cm2; The answer is (A).
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q: A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 290 m long?
Options:
(A) 40 sec
(B) 52 sec
(C) 45 sec
(D) 48 sec
(E) 50 sec
a: Speed = 45 * 5/18 = 25/2 m/sec
Total distance covered = 360 + 290 = 650 m
Required time = 650 * 2/25 = 52 sec The answer is (B).
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q: What number comes next in the following series? 4, 13, 40, 121, 364, x
Options:
(A) 1093
(B) 1100
(C) 1301
(D) 1400
(E) 1713
a:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
4
4 × 3 + 1 = 13
13 × 3 + 1 = 40
40 × 3 + 1 = 121
121 × 3 + 1 = 364
364 × 3 + 1 = 1093 The answer is (A).
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