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.
--------
Question: Problem: 108 a 108 + 92 a 92 = ?
Options: a. 20120, b. 11500, c. 20128, d. 20660, e. 20228

Answer: c

Question: Problem: a cyclist bikes x distance at 8 miles per hour and returns over the same path at 10 miles per hour. what is the cyclist ' s average rate for the round trip in miles per hour ?
Options: a. 8.1, b. 8.9, c. 8.6, d. 8.3, e. 9.0

Answer: b

Question: Problem: three numbers are in the ratio 4: 5: 6 and their product is 76680. the largest number is
Options: a. 30, b. 24, c. 26, d. 28, e. 22

Answer:
b