Final answer:
The unit rate price per ounce for Rosie's hot chocolate is $0.25, calculated by dividing the total cost by the quantity of the product received.
Step-by-step explanation:
To calculate the unit rate price per ounce for Rosie's hot chocolate, we need to divide the total price she paid by the number of ounces in the cup.
Price per ounce = Total price ÷ Number of ounces
Price per ounce = $5.00 ÷ 20 oz
Price per ounce = $0.25 per ounce
Therefore, the unit rate for the hot chocolate is $0.25 per ounce.