Let's denote the amount of flour in the original recipe as \( F \) cups.
According to the information given in the problem:
- The original recipe makes 4 loaves.
- The original recipe calls for 2 cups of sugar.
- The combined amount of flour and sugar in Kendra's changed recipe for one loaf is \( 2.5 \) cups.
Since the original recipe makes 4 loaves, we can find the amounts for one loaf by dividing each ingredient by 4.
The amount of sugar for one loaf would be: \[ \frac{2 \text{ cups of sugar}}{4} = 0.5 \text{ cups of sugar} \]
Let’s denote the total amount of flour for the original recipe as \( F \). For one loaf, the flour amount will be: \[ \frac{F}{4} \text{ cups of flour} \]
Now, for the changed recipe, we have: \[ \frac{F}{4} + 0.5 = 2.5 \]
To find \( F \), we can rearrange the equation: \[ \frac{F}{4} = 2.5 - 0.5 \] \[ \frac{F}{4} = 2.0 \]
Now, we’ll multiply both sides by 4: \[ F = 2.0 \times 4 \] \[ F = 8 \text{ cups of flour} \]
So, the amount of flour in the original recipe is \( \boxed{8} \) cups.