Answer
At 0.60/ounce, the 12 ounce package is the best buy.
Work Step by Step
$\frac{6.79}{11 ounce}$ = $\frac{6.79\div11}{11\div11 ounce}$ = $\frac{0.62}{1 ounce}$ = 0.62/ounce
$\frac{7.24}{12 ounce}$ = $\frac{7.24\div12}{12\div12 ounce}$ = $\frac{0.60}{1 ounce}$ = 0.60/ounce
$\frac{10.99}{16 ounce}$ = $\frac{10.99]div16}{16\div16 ounce}$ = $\frac{0.69}{1 ounce}$ = 0.69/ounce
