To find the unit rate price per ounce for the hot chocolate, you divide the total cost by the number of ounces.
Cost of hot chocolate = $5.00
Volume of hot chocolate = 20 oz
Unit rate price per ounce = Total cost / Volume = $5.00 / 20 oz = $0.25 per ounce
So, the unit rate price per ounce for her hot chocolate is $0.25.