Final answer:
To find the percentage discount from a $10 retail price to a $5.50 sale price, calculate the difference, divide by the original price, and multiply by 100. The answer is a 45% discount.
Step-by-step explanation:
To determine the percentage discount off the retail price of $10 that results in a sale price of $5.50, we can set up the following equation:
Discount % = ((Retail Price - Sale Price) / Retail Price) * 100
Plugging in the values, we get:
Discount % = (($10 - $5.50) / $10) * 100
Discount % = ($4.50 / $10) * 100
Discount % = 0.45 * 100
Discount % = 45%
Therefore, a 45% discount off the retail price of $10 is needed to reduce the price to $5.50.