To calculate the amount of flour needed for 1 cup of sugar, we can set up a proportion using the information given in the recipe:
2 1/2 cups of flour for every 1/4 cup of sugar
1 cup of sugar is equal to 4 1/4 cups (since 4 1/4 = 1)
So, we can set up the proportion:
2 1/2 cups of flour / (1/4) cup of sugar = X cups of flour / 1 cup of sugar
Simplifying:
2.5 / 0.25 = X / 1
10 = X
Therefore, Eric should use 10 cups of flour for every 1 cup of sugar.