College Math Placement Practice Test

To determine the correct expression that represents Tim's savings from a 20% discount on a $42.50 purchase, we need to understand how to calculate a percentage discount. The formula to find the discount amount is to multiply the original price by the percentage discount expressed as a decimal. In this case, the original price of the purchase is represented as \( d \), which is $42.50, and the percentage discount is 20%. To convert 20% into decimal form, you divide the percentage by 100: \[ 20\% = \frac{20}{100} = 0.20 \] Then, to find the savings, you multiply the original price \( d \) by the decimal form of the discount: \[ \text{Savings} = d \times 0.20 \] This expression accurately calculates the amount saved due to the discount. In contrast, the other choices do not correctly represent the calculation of a percentage discount. For example, multiplying by 20 would give a value 20 times the purchase price rather than the discount. Dividing by 0.20 or 20 would not yield the discount amount because those operations don’t compute the savings from a percentage