ANSWERS
a) Regular $ 0.21 per ounce
Family size $ 0.19 per ounce
b) Family size
Step-by-step explanation
To find the unit rates we have to divide the price by the amount of ounces:
For regular peanut butter:
For family size:
The one that has a smaller unit rate is a better buy. In this case, the family size is a better buy.