We will have that the better deal is determined as follows:
[tex]D=\frac{4.39}{11.5}\Rightarrow D\approx0.38[/tex][tex]C=\frac{2.24}{9.75}\Rightarrow C\approx0.23[/tex]D being for Doritos and C for Cheetos.
We can see that the better deal is buying the Cheetos since the unit oz cost approximately $0.23.