In a cost problem, the last step is to divide

In a cost problem, the last step is to divide

• A. the recent sales price by the decimal found in step 2
• B. the decimal by the recent sales price
• C. the decimal by the original price
• D. the original price by the decimal

Answer: (A)

When a price is adjusted by a percent, the sale price is the original price multiplied by a decimal (for example, a discount uses a decimal less than 1). To recover the original price, you undo that multiplication by dividing the sale price by the same decimal. So dividing the recent sales price by the decimal found in step 2 is the correct last step: you’re reversing the effect of the percentage change. Example: original price $100 with a 20% discount gives a sale price of $80. The decimal is 0.80, and 80 ÷ 0.80 = 100, which returns the original price. Dividing the decimal by the sale price or dividing the original price by the decimal would not undo the discount properly, and dividing the sale price by the decimal is the operation that reverses the multiplication by the decimal.

When a price is adjusted by a percent, the sale price is the original price multiplied by a decimal (for example, a discount uses a decimal less than 1). To recover the original price, you undo that multiplication by dividing the sale price by the same decimal. So dividing the recent sales price by the decimal found in step 2 is the correct last step: you’re reversing the effect of the percentage change.

Example: original price $100 with a 20% discount gives a sale price of $80. The decimal is 0.80, and 80 ÷ 0.80 = 100, which returns the original price.

Dividing the decimal by the sale price or dividing the original price by the decimal would not undo the discount properly, and dividing the sale price by the decimal is the operation that reverses the multiplication by the decimal.