20 oz package of harm cost $8.75
3lb package of harm cost $15.60
[tex]\begin{gathered} \text{ The cost per ounce of the 20 0z package }=\frac{8.75}{20}\text{ dollars per ounce} \\ =43.75\text{ cents per ounc}e \end{gathered}[/tex]And
[tex]\begin{gathered} \text{ The cost per ounce of the 3lb package }=\frac{15.60}{3\times16}\text{ dollars per ounce} \\ =32.50\text{ cents per ounce} \end{gathered}[/tex]The difference in the cost is
[tex]43.75-32.50=11.25[/tex]Hence he will save 11.3 cents per ounce in buying 3-lb package
The third option is correct
