Answer
The 8oz bottle is \$0.149/oz.
The 12oz bottle is \$0.158/oz
The 8oz bottle is the better buy
Work Step by Step
A unit rate has 1 in the denominator.
$\frac{\$1.19}{8oz}=\frac{\$1.19\div8}{8oz\div8}=\frac{\$0.14875}{1oz}$
$\frac{\$1.89}{12oz}=\frac{\$1.89\div12}{12oz\div12}=\frac{\$0.1575}{1oz}$