24 inches goes how many times into 135sqft?

Let's see. This is a math question, not a question of interior design. The first question is; are you using 24 square inches to divide into 135 sq ft.? Otherwise, it is like dividing Apples by Oranges. If they are square inches, you can convert the square feet to square inches, or the square inches to square feet and then divide. There are 144 square inches in a square foot.