Set up a proportion:
[tex]\frac{1}{5.7} = \frac{3}{x}[/tex]
The numerator represents the pounds of trail mix, and the denominator represents the ounces of raisins needed to create the pounds of trail mix.
Cross multiply the fractions:
[tex]1 \cdot x = 5.7 \cdot 3[/tex]
[tex]\boxed{x = 17.1}[/tex]
The answer will be C. 17.1 oz.
