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: the ratio of the present age of viju to that of aju is 7: 2. 4 years from now, the ratio of the ages of viju to aju will be 5: 2. what was viju age 5 years ago ? ( rbi assistant 2015 )
Options: a. 24, b. 18, c. 12, d. 16, e. 13
answer:
d

question:
Problem: find the simple interest on rs. 72,000 at 16 2 / 3 % per year for 9 months.
Options: a. 7500, b. 6500, c. 9000, d. 9500, e. none of them
answer:
c

question:
Problem: carl is facing very difficult financial times and can only pay the interest on a $ 10,000 loan he has taken. the bank charges him a quarterly compound rate of 8 %. what is the approximate interest he pays annually ?
Options: a. 1500, b. 1750, c. 2000, d. 3500, e. 2500
answer:
d