Apair of shoes costs $30.99 and the state sales tax is 5%. use the formula c = p + rp to find the total cost of the shoes, where c is the total cost, p is the price, and r is the sales tax rate.

First, write the rate as a decimal by moving the decimal point two places to the left from the percent.

r = 5% = 0.05

C = p + rp

C = 30.99 + 0.05 * 30.99

C = 30.99 + 1.55

C = 32.54

The total cost is $32.54