Exercise 5 Page 181

We want to find the sale price of the radio. Let's start by calculating the dollar amount of the discount. We can do this by using the percent equation. part = percent * whole We are given that the regular price of the radio is $ 30, and the discount is 40 %. Let d represent the dollar amount of the discount. d = 40 % * $ 30Before solving the equation that we got, let's write the percent as a decimal. We can do this by ignoring the percent symbol and moving the decimal point two places to the left.

We got that 40 % is equal to 0.40 or 0.4. d = 40 % * $ 30 [0.3em] ⇓ [0.3em] d = 0.4 * $ 30 Finally, we will solve the equation for d. For simplicity, we will omit the dollar symbol.

We found that d = 12 is a solution to the equation. This means that the dollar amount of the discount is $ 12. Now we can calculate the sale price of the radio by subtracting $ 12 from the regular price. $ 30 - $ 12 = $ 18 The sale price of the radio is $ 18.