Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

Q: Problem: the average age of 17 persons in a office is 15 years. out of these, the average age of 5 of them is 14 years and that of the other 9 persons is 16 years. the age of the 15 th person is ?
Options: a. 39, b. 41, c. 45, d. 42, e. 50

A: b
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Q: Problem: if x and y are positive integers and 3 + x + y + xy = 17, what is the value of x + y ?
Options: a. 3, b. 5, c. 6, d. 8, e. 9

A: c
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Q: Problem: two trains are moving in the same direction at 108 kmph and 54 kmph. the faster train crosses a man in the slower train in 24 seconds. find the length of the faster train ?
Options: a. 320, b. 330, c. 340, d. 350, e. 360

A:
e
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