Final answer:
To calculate the unit rate price per ounce for hot chocolate, divide the total cost ($5.00) by the total ounces (20 oz), resulting in $0.25 per ounce.
Step-by-step explanation:
To find the unit rate price per ounce for Rosie's hot chocolate, we divide the total cost of the hot chocolate by the number of ounces she receives. Rosie pays $5.00 for a 20 oz. cup of hot chocolate.
Unit rate = Total Cost ÷ Number of Ounces
Unit rate = $5.00 ÷ 20 oz
Unit rate = $0.25 per ounce
Thus, the unit rate price per ounce of Rosie's hot chocolate is $0.25.