Detailed Instructions: 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.
See one example below:
Problem: Problem: a multiple choice test consists of 4 questions, and each question has 5 answer choices. in how many r ways can the test be completed if every question is unanswered ?
Options: a. 24, b. 120, c. 625, d. 720, e. 1024
Solution: c
Explanation: 5 choices for each of the 4 questions, thus total r of 5 * 5 * 5 * 5 = 5 ^ 4 = 625 ways to answer all of them. Hence, the answer is c.

Problem: Problem: maths, physics and chemistry books are stored on a library shelf that can accommodate 25 books. currently, 20 % of the shelf spots remain empty. there are twice as many maths books as physics books and the number of physics books is 4 greater than that of chemistry books. among all the books, 12 books are soft cover and the remaining are hard - cover. if there are a total of 7 hard - cover books among the maths and physics books. what is the probability q, that a book selected at random is either a hard cover book or a chemistry book ?
Options: a. 1 / 10, b. 3 / 20, c. 1 / 5, d. 1 / 4, e. 9 / 20
Solution:
e