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.
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Question: Problem: cereal a is 10 % sugar by weight, whereas healthier but less delicious cereal b is 2 % sugar by weight. to make a delicious and healthy mixture that is 3 % sugar, what should be the ratio of cereal a to cereal b, by weight ?
Options: a. 2: 9, b. 2: 7, c. 1: 7, d. 1: 4, e. 1: 3

Answer: c

Question: Problem: the lcm of two numbers is 2310 and hcf is 55. if one of the numbers is 210. then what is the other number ?
Options: a. 715, b. 825, c. 330, d. 605, e. 465

Answer: d

Question: Problem: a teacher grades students ' tests by subtracting twice the number of incorrect responses from the number of correct responses. if student a answers each of the 100 questions on her test and receives a score of 76, how many questions did student a answer correctly ?
Options: a. 92, b. 60, c. 73, d. 82, e. 91

Answer:
a