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 certain protective additive increases from 50 days to 60 days the time between required maintenance checks on an industrial vehicle. by what percent is the time between maintenance checks increased by using the additive ?
Options: a. 25 %, b. 33 1 / 3 %, c. 50 %, d. 66 2 / 3 %, e. 20 %

SOLUTION: e

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: 5 % of ( 25 % of $ 1600 ) is ?
Options: a. $ 20, b. $ 30, c. $ 45, d. $ 15, e. $ 60

SOLUTION:
a