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: ages of two persons differ by 20 years. if 6 year ago, the elder one be 3 times as old the younger one, find their present age
Options: a. 12,28, b. 14,30, c. 16,36, d. 18,34, e. 19,34

A: c
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Q: Problem: a train traveling at 72 kmph crosses a platform in 33 seconds and a man standing on the platform in 18 seconds. what is the length of the platform in meters ?
Options: a. 240 meters, b. 360 meters, c. 420 meters, d. 300 meters, e. can not be determined

A: d
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Q: Problem: joe ’ s average ( arithmetic mean ) test score across 4 equally weighted tests was 70. he was allowed to drop his lowest score. after doing so, his average test score improved to 75. what is the lowest test score that was dropped ?
Options: a. 20, b. 25, c. 55, d. 65, e. 80

A:
c
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