Part A:
Since she will be serving French toast for 12 people, Dora needs to scale her ingredients 6 times. The recipe calls for 2 servings, therefore, creating 6 × 2 = 12 servings.
Ingredients
2 eggs × 6 = 12 eggs
3/4 teaspoon sugar × 6 = 18/4 teaspoon sugar → 4 1/2 teaspoon sugar
1/4 teaspoon salt × 6 = 6/4 teaspoon salt → 1 1/2 teaspoon salt
1/2 cup milk × 6 = 6/2 cup milk → 3 cups milk
4 slices white bread × 6 = 24 slices white bread.
Part B:
If Dora uses the same recipe just for herself (1 serving only), given that the recipe makes 2 servings. All she needs to do is to divide everything in the recipe by 2, and she will be able to make french toast for only 1 serving.