Solve for the unit price of 11.5-ounce package.
Divide the cost by the number of ounce of the package.
$4.24 ÷ 11.5 oz = $0.3690 per ounce
Rounding off to the nearest cent → $0.37 per ounce.
Solve for the unit price of 27.8-ounce package
Do the same as above with its corresponding cost.
$9.98 ÷ 27.8 oz = 0.359 per ounce
Rounding off to the nearest cent → $0.36 per ounce.
Comparing the two, the 27.8-ounce package is much cheaper per ounce than with the 11.5-ounce package, thus the 27.8-ounce package is a better buy.