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.

[Q]: Problem: if 80 percent of a class answered the first question on a certain test correctly, 55 percent answered the second question on the test correctly, and 20 percent answered neither of the questions correctly, what percent answered both correctly ?
Options: a. 10 %, b. ( 8 ) 20 %, c. 30 %, d. 50 %, e. 55 %
[A]: e

[Q]: Problem: in a mayoral election, candidate x received 1 / 2 more votes than candidate y, and candidate y received 2 / 5 fewer votes than z. if z received 25000 votes how many votes did candidate x received ?
Options: a. 18000, b. 22500, c. 24000, d. 26000, e. 32000
[A]: b

[Q]: Problem: if 15 % of 30 % of 50 % of a number is 108, then what is the number ?
Options: a. 4000, b. 3050, c. 4400, d. 4800, e. none of these
[A]:
d