The answer is c. I chose the answer c because y=5/2x(I think you forgot to put the x in the question) filled in with the numbers are true while a, b, and d aren't true if filled with 10 and 4.
Cost of the article = $27.50 Amount of city sales tax = (27.50 x 6%) = $1.65 Amount of excise tax = (27.50 x 8%) = $2.20 From my knowledge, we pay city sales tax and federal excise tax when we buy something, so the total cost would be $31.35