You are given a mathematical question described with an open-ended vocabulary. Questions in this task involve real-world situations, describing a mathematical problem. You are also given 4 or 5 answer options (associated with "A", "B", "C", "D", "E"). Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'. LaTeX mathematical format (the standard way to express mathematical expressions in the typesetting software known as LaTeX) is used to express equations. Each question is solvable with high school math knowledge. Give only one answer for each question.

[EX Q]: A local store donated some markers to Mrs. Kettz's fourth-grade class. If each student takes 2 markers, there will be 16 markers left. If 4 students do not take any markers and the rest of the students take 6 markers, there will be no markers left. How many markers were donated to the class?
(A)24 (B)30 (C)36 (D)40 (E)48
[EX A]: C

[EX Q]: In a class, 20 children were sharing equally the cost of a present for their teacher. When 4 of the children decided not to contribute, each of the other children had to pay \$1.50 more. How much, in dollars, did the present cost?
(A)50 (B)80 (C)100 (D)120 (E)150
[EX A]: D

[EX Q]: The cost of a meal including a 20 percent tip is \$30. What was the cost of the meal before the tip was added?
(A)\$10.00 (B)\$24.00 (C)\$25.00 (D)\$29.80 (E)\$36.00
[EX A]:
C