jmc

We could solve this problem by figuring out the per-ounce cost of the 48-ounce package, increasing it by $25\%$, and then multiplying that by 32 for the smaller package. However, if we simply increase the price by $25\%$, and then scale the package size down to 32 ounces from 48 ounces, these are the same calculations, but in a different order that makes it easier to calculate. Thus: $3.90\times 1.25\times \frac{32}{48}=\boxed{3.25\text{ dollars}}$