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: how much is 60 % of 40 is greater than 4 / 5 of 30 ?
Options: a. 8, b. 3, c. 7, d. 0, e. 1

Answer: d

Question: Problem: if the ratio of two number is 6: 7 and lcm of the number is 450 then what is the number.
Options: a. 11, b. 20, c. 25, d. 30, e. 35

Answer: a

Question: Problem: a person borrows 20000 for 6 years at 8 % p. a. simple interest. he immediately lends it to another person at 9 % p. a. for 6 years. find his gain in the transaction per year.
Options: a. 200, b. 250, c. 210, d. 190, e. 180

Answer:
a