question: If six persons sit in a row, then the probability that three particular persons are always together is ?
Options:
(A) 1/6
(B) 1/2
(C) 1/5
(D) 1/2
(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: 3 candidates in an election and received 4136, 7636 and 11628 votes respectively. What % of the total votes did the winning candidate got in that election?
Options:
(A) 45%
(B) 49%
(C) 50%
(D) 59%
(E) 61%
answer: Stream of consciousness: Total number of votes polled = (4136 + 7636 + 11628) = 23400
So, Required percentage = 11628/23400 * 100 = 50% The answer is (C).
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question: Eddy and Freddy start simultaneously from city A and they travel to City B and City C respectively. Eddy takes 3 hours and Freddy takes 4 hours to complete the journey. If the distance between City A and City B is 600 kms and City A and City C is 360 kms. What is the ratio of their average speed of travel? (Eddy: Freddy)
Options:
(A) 8/3
(B) 3/8
(C) 8/5
(D) 5/8
(E) 20/9
answer: Stream of consciousness: Distance traveled by Eddy = 600 km
Time taken by Eddy = 3 hours
Average speed of Eddy = 600/3 = 200 km/hour
Distance traveled by Freddy = 360 km
Time taken by Freddy = 4 hours
Average speed of Freddy = 360/4 = 90 km/hour
Ratio of average speed of Eddy to Freddy = 200/90 = 20/9 The answer is (E).
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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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