Final answer:
Johnny will need 0.5 onions to make 4 servings of chicken parmesan.
Step-by-step explanation:
To determine how many onions Johnny will need to make 4 servings of chicken parmesan when the recipe calls for 1 onion for 8 servings, you can use a proportion to find the answer.
First, set up the proportion: 1 onion / 8 servings = x onions / 4 servings.
Cross-multiply and solve for x:
1 * 4 = 8 * x
4 = 8x
x = 4/8
x = 0.5
So, Johnny will need 0.5 onions to make 4 servings of chicken parmesan.