question: Two trains are moving at 65 kmph and 70 kmph in opposite directions. Their lengths are 150 m and 100 m respectively. The time they will take to pass each other completely is?
Options:
(A) 6 2/3 sec
(B) 7 1/7 sec
(C) 7 2/2 sec
(D) 8 1/2 sec
(E) 7 1/9 sec
answer: Stream of consciousness: 70 + 65 = 135 * 5/18 = 75/2 mps
D = 150 + 100 = 250 m
T = 250 * 2/75 = 20/3 - 6 2/3 sec The answer is (A).
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question: A can do a certain work in 12 days. B is 60% more efficient than A. How many days does B alone take to do the same job ?
Options:
(A) 19
(B) 15
(C) 16
(D) 17
(E) 18
answer: Stream of consciousness: Ratio of time taken by A & B = 160:100 = 8:5 Suppose B alone takes x days to do the job. Then, 8:5::12:x = > 8x = 5*12 = > x = 15 days. The answer is (B).
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question: 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
answer: 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 gallons\
Volume of whole = 3 * 40 = 120 gallons. The answer is (C).
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question: If the ratio of ages of two friends is 4:3 and sum of their ages is 70 years then what is the age of older friend?
Options:
(A) 30 years
(B) 35 years
(C) 40 years
(D) 25 years
(E) 45 years
answer:

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
Stream of consciousness: Sum of thier ages is 70 in ratio 4:3
So 40+30 gives us 70. Wich is 4:3 so, older guy is having 40. The answer is (C).
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