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: what is the normal price of an article sold at $ 72 after two successive discounts of 10 % and 20 % ?
Options: a. $ 92, b. $ 96, c. $ 100, d. $ 104, e. $ 108

A: c
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Q: Problem: an article is bought for rs. 675 and sold for rs. 900, find the gain percent ?
Options: a. 33 1 / 8 %, b. 33 9 / 3 %, c. 33 1 / 3 %, d. 93 1 / 3 %, e. 33 2 / 3 %

A: c
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Q: Problem: a train consists of 48 boxcars pulled by 2 engines. the boxcars are 15 meters long and the two engines are each 20 meters long. it crosses over a highway 24 meters wide at a speed of 14 m / s. how long does it take for the entire train to cross ?
Options: a. 56 sec, b. 63 sec, c. 72 sec, d. 81 sec, e. 88 sec

A:
a
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