q: A train running at the speed of 60 km/hr crosses a pole in 15 sec. What is the length of the train?
Options:
(A) 118
(B) 150
(C) 277
(D) 250
(E) 191
a: Speed = 60 * 5/18 = 50/3 m/sec
Length of the train = speed * time = 50/3 * 15 = 250 m The answer is (D).
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q: The average age of 11 boys is 50, if the average age of first six boys is 49 and that of the last six is 52. Find the boy age?
Options:
(A) 48
(B) 50
(C) 56
(D) 62
(E) 64
a: 1 to 11 = 11 * 50 = 550
1 to 6 = 6 * 49 = 294
6 to 11 = 6 * 52 = 312
6th = 294 + 312 550 = 56 The answer is (C).
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q: The average of 11 results is 49, if the average of first six results is 49 and that of the last six is 52. Find the sixth result?
Options:
(A) 21
(B) 67
(C) 18
(D) 25
(E) 23
a: 1 to 11 = 11 * 49 = 539
1 to 6 = 6 * 49 = 294
6 to 11 = 6 * 52 = 312
6th = 294 + 312 539 = 67 The answer is (B).
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q: 3 friends A, B, C went for week end party to McDonald's restaurant and there they measure there weights in some order In 7 rounds. A, B, C, AB, BC, AC, ABC. Final round measure is 140kg then find the average weight of all the 7 rounds?
Options:
(A) 98.5 kgs
(B) 80 kgs
(C) 76.5 kgs
(D) 67.5 kgs
(E) 58.2 kgs
a:
Average weight = [(a + b + c + (a+b) + (b+c) + (c+a)+(a+b+c)] / 7 = 4 (a+b+c) /7 = 4 x 140/7 = 80 kgs The answer is (B).
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