Answer
The lower unit cost is $0.913/ounce so the best buy is the 4 ounce container.
Work Step by Step
$\frac{\$ 2.25}{2 ounce}$ = $\frac{\$ 2.25\div2}{2\div2 ounce}$ = $\frac{\$ 1.125}{1 ounce}$ = $\$1.125/ounce$
$\frac{\$ 3.65}{4 ounce}$ = $\frac{\$ 3.65\div4}{4\div4 ounce}$ = $\frac{\$ 0.9125}{1 ounce}$ = $\$0.913/ounce$
