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: a person buys an article at $ 600. at what price should he sell the article so as to make a profit of 8 % ?
Options: a. 670, b. 689, c. 648, d. 740, e. 889
answer:
c

question:
Problem: two trains of equal are running on parallel lines in the same direction at 45 km / hr and 36 km / hr. the faster train passes the slower train in 36 sec. the length of each train is ?
Options: a. 45, b. 88, c. 66, d. 55, e. 22
answer:
a

question:
Problem: p, q and r have rs. 7000 among themselves. r has two - thirds of the total amount with p and q. find the amount with r ?
Options: a. rs. 3000, b. rs. 3600, c. rs. 2400, d. rs. 2800, e. none of these
answer:
d