Answer
The 16oz jar is \$0.093/oz.
The 24 oz jar is \$0.100/oz.
The 16oz jar is the better buy.
Work Step by Step
A unit rate has 1 in the denominator.
$\frac{\$1.49}{16oz}=\frac{\$1.49\div16}{16oz\div16}=\frac{\$0.093125}{1oz}$
$\frac{\$2.39}{24oz}=\frac{\$2.39\div24}{24oz\div24}=\frac{\$0.09958\overline3}{1oz}$