Answer:
KArl should use 3/16 cups of chili powder
Explanation:
Given that:
Recipe's requirement : 3/8 cups
Karl wants to use half : 1/2
The given question involves fractions. When the number of cups has to be divided into half, it will be multiplied with 1/2.
So,
Multiplying the chili powder requirement of the recipe to 1/2

Hence,
KArl should use 3/16 cups of chili powder