For each burrito we need 3 ounces of cheese. For each taco we need 2 ounces of cheese.
So for 9 burritos we need 27 ounces of cheese, because each burrito needs 3 ounces of cheese.
And for, 1 taco we just need 2 ounces of cheese.
27 + 2 = 29 ounces of cheese