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.
Problem:Problem: a customer went to a shop and paid a total of $ 30, out of which 90 cents was for sales tax on taxable purchases. if the tax rate was 6 %, then what was the cost of the tax free items ?
Options: a. $ 12.70, b. $ 13.20, c. $ 14.10, d. $ 15.60, e. $ 16.80
Solution:
c