In this problem the vital information that Catherine is making 2 gallons of punch is already provided. The vital information that is required is to find out the number of cups in 1 gallon. Once this information is in hand then the problem becomes one of the easiest problem. Although the number of cups in one gallon varies from country to country but we have to find the number of cups per gallon in US.
1 gallon = 16 cups
Then
2 gallons = (16 * 2) cups
= 32 cups
So Catherine will make a total of 32 cups from 2 gallons for her party.