instruction:
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.
question:
Problem: two trains of equal length are running on parallel lines in the same directions at 46 km / hr. and 36 km / hr. the faster trains pass the slower train in 72 seconds. the length of each train is :
Options: a. 82 m, b. 50 m, c. 72 m, d. 100 m, e. none of these
answer:
d


question:
Problem: bill made a profit of 10 % by selling a product. if he had purchased that product for 10 % less and sold it at a profit of 30 %, he would have received $ 63 more. what was his original selling price ?
Options: a. $ 850, b. $ 990, c. $ 1050, d. $ 1180, e. $ 1340
answer:
b


question:
Problem: robert ' s salary was decreased by 20 % and subsequently increased by 20 %. how much percentage does he lose ?
Options: a. 4 %, b. 20 %, c. 25 %, d. 30 %, e. 50 %
answer:

a