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.
Q: Problem: in a university the average age in an arts class is 21 and average age in technical class is 18. what is the age average of university if there are 8 arts classes and 5 technical classes ?
Options: a. 18.75, b. 19.85, c. 20.32, d. 20.9, e. 21.0
A:
b