Answer:
9 ounces
Explanation:
Let x be the ounces left in the box.
Given:
Total ounces in box = 24
Cara has eaten 3/8 of the box,
So, Cara eaten =

Cara eaten =

Cara eaten =

Cara eaten =

So, Cara has eaten 9 ounce of the box of cereal.
Glen has eaten 1/4 of the box of cereal.
So, Glan eaten =

Glan eaten =

Glan eaten =

Glan eaten =

So, Glan has eaten 6 ounce of the box of cereal.
Therefore, the sum of the Cara and Glan ounces =
.
So total left ounces in box = 24-15 = 9
Therefore, The ounces left in the box is 9.