instruction:
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: 210 students were asked in a survey if they preferred windows or mac brand computers. 60 students claimed that they preferred mac to windows brand computers. one third as many of the students who preferred mac to windows, equally preferred both brands. 90 of the students had no preference. how many of the students in the survey preferred windows to mac brand computers ?
Options: a. 25, b. 40, c. 50, d. 60, e. 75
answer:
b

question:
Problem: a is twice as good a work man as b and together they finish the work in 4 days. in how many days a alone can finish the work ?
Options: a. 3, b. 2, c. 7, d. 9, e. 6
answer:
e

question:
Problem: if 45 % of a class averages 95 % on a test, 50 % of the class averages 78 % on the test, and the remainder of the class averages 60 % on the test, what is the overall class average ? ( round final answer to the nearest percent ).
Options: a. 83 %, b. 84 %, c. 85 %, d. 86 %, e. 87 %
answer:
c