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.

Problem: if the simple interest on a certain amount in at 4 % rate 5 years amounted to rs. 2240 less than the principal. what was the principal ?
Options: a. 1500, b. 2500, c. 2507, d. 2800, e. 11500
d

Problem: the total age of a and b is 15 years more than the total age of b and c. c is how many year younger than
Options: a. 14 years, b. 12 years, c. 56 years, d. 66 years, e. 15 years
e

Problem: the average ( arithmetic mean ) of all scores on a certain algebra test was 90. if the average of the 8 male students ’ grades was 84, and the average of the female students ’ grades was 92, how many female students took the test ?
Options: a. 8, b. 9, c. 10, d. 21, e. 24

e