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.

[EX Q]: Problem: aaron will jog from home at 2 miles per hour and then walk back home by the same route at 4 miles per hour. how many miles from home can aaron jog so that he spends a total of 3 hours jogging and walking ?
Options: a. 5, b. 7, c. 3, d. 9, e. 10
[EX A]: c

[EX Q]: Problem: a waitress ' s income consists of her salary and tips. during one week, her tips were 3 / 4 of her salary. what fraction of her income for the week came from tips ?
Options: a. 1 / 9, b. 1 / 6, c. 3 / 7, d. 4 / 9, e. 5 / 9
[EX A]: c

[EX Q]: Problem: the average age of 20 students of a class is 20 years. out of these, the average age of 9 students is 11 years and that of the other 10 students is 24 years. the age of the 20 th student is ?
Options: a. 65, b. 61, c. 59, d. 63, e. 64
[EX A]:
b