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: if a man lost 8 % by selling oranges at the rate of 25 a rupee at how many a rupee must he sell them to gain 25 % ?
Options: a. 20, b. 15, c. 18.4, d. 20, e. 12.8
answer:
c


question:
Problem: cost is expressed by the formula tb ^ 4. if b is doubled, the new cost w is what percent of the original cost ?
Options: a. w = 200, b. w = 600, c. w = 800, d. w = 1600, e. w = 50
answer:
d


question:
Problem: two pipes a and b can fill a tank in 24 minutes and 32 minutes respectively. if both the pipes are opened simultaneously, after how much time should b be closed so that the tank is full in 18 minutes ?
Options: a. 7 minute, b. 9 minute, c. 10 minute, d. 8 minute, e. 11 minute
answer:

d