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 bag of potatoes weighs 60 lbs divided by half of its weight. how much does the bag of potatoes weight ?
Options: a. 20 lb, b. 11 lb, c. 10 lb, d. 15 lb, e. 5 lb
[EX A]: b

[EX Q]: Problem: the average marks obtained by 50 candidates in a certain examination is 40. find the total marks.
Options: a. 1800, b. 2000, c. 1640, d. 2200, e. 2400
[EX A]:
b