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: buses a and b start from a common bus stop x. bus a begins to travel in a straight line away from bus b at a constant rate of 20 miles per hour. one hour later, bus b begins to travel in a straight line in the exact opposite direction at a constant rate of 80 miles per hour. if both buses travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes bus b to cover the exact distance that bus a has covered and the amount of time it takes bus b to cover twice the distance that bus a has covered ?
Options: a. 36, b. 72, c. 132, d. 144, e. 180

SOLUTION: c

PROBLEM: Problem: the perimeter of an isosceles right triangle is 12 + 12 sq rt 2. what is the length of the hypotenuse of the triangle ?
Options: ['a. 5', 'b. 6', 'c. 7', 'd. 8.485', 'e. 8']

SOLUTION: d

PROBLEM: Problem: a man goes downstream at 10 kmph, and upstream 8 kmph. the speed of the stream is
Options: a. 0 kmph, b. 4 kmph, c. 1 kmph, d. 2.5 kmph, e. 26 kmph

SOLUTION:
c