Mathematics (elementary)

Question

the sales tax on a car that sold for $13,500 is $810. at this rate, how much higher is the tax on a car that sells for $16,500

Answer 1

Sales tax is a constant proportion of original price

sales tax of 810 out of 13500 is a proportion of 810/13500 = 6/100

we just take the same proportion of 16500 giving (6/100) x 16500

16500 / 100 = 165

6 x 165 = 990

so new tax = 990

difference = 990 - 810 = 180.