Answer:
18 oz
Step-by-step explanation:
Choco Chip Cookies (15 oz): [tex]\frac{\$3.20}{15oz}=\frac{\$0.213}{oz}[/tex]
Choco Chip Cookies (18 oz): [tex]\frac{\$3.75}{18oz}=\frac{\$0.208}{oz}[/tex]
So, the 18oz package is the better buy by about [tex]\$0.005[/tex]