Answer: 1 2/3 ounces of cinnamon is needed.
Explanation:
1/3 ounce is cinnamon is needed for each 1 and 1/2 cups of flour. Converting 1 and 1/2 cups to improper fraction, it becomes 3/2 cups.
It means that the number of ounces of cinnamon need for 1 cup of flour would be
(1/3)/(3/2) = 1/3 × 2/3 = 2/9 ounces of cinnamon.
Converting 7 and 1/2 cups of flour to improper fraction, it becomes 15/2 cups of flour.
Therefore, the ounces of cinnamon needed to bake cookies with 15/2 cups of flour is
2/9 × 15/2 = 15/9 = 5/3
= 1 2/3 ounces of cinnamon