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 jar contained red and green marbles in a ratio of 3 to 4. After 6 red marbles are added to the jar, the ratio becomes 3 to 2. How many green marbles does the jar now contain?
(A)3 (B)4 (C)6 (D)8 (E)14
[EX A]: D

[EX Q]: Steve took a bike trip in which he covered half the total distance on Monday. After going 100 kilometers on Tuesday, he determined that he still had 10\% of the trip to complete. What was the total length, in kilometers, of the trip?
(A)200 (B)250 (C)400 (D)500 (E)600
[EX A]: B

[EX Q]: If it takes 10 people 18 hours to do a certain job, how many hours would it take 15 people, working at the same rate, to do \(\frac { 2 } { 3 } \) of the same job?
(A)6 (B)8 (C)9 (D)10 (E)12
[EX A]:
B