TASK DEFINITION: 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: Problem: a can do a job in 15 days and b in 20 days. if they work on it together for 4 days, then the fraction of the work that is left is ?
Options: a. 2 / 15, b. 8 / 15, c. 3 / 11, d. 1 / 12, e. 6 / 13

SOLUTION: b

PROBLEM: Problem: mary works in a restaurant a maximum of 70 hours. for the first 20 hours, she is paid $ 8 per hour. for each overtime hour, she is paid at a rate which is 25 % higher than her regular rate. how much mary can earn in a week ?
Options: a. 600, b. 620, c. 660, d. 320, e. 400

SOLUTION: c

PROBLEM: Problem: in a certain game, each player scores either 2 points or 5 points. if n players score 2 points and m players score 5 points, and the total number of points scored is 50, what is the least possible positive difference w between n and m ?
Options: a. 1, b. 3, c. 5, d. 7, e. 9

SOLUTION:
b