Answer:
85 tiles.
Step-by-step explanation:
In order to solve this problem we first need to calculate the Square Footage of the floor. We do this by multiplying the width and length of the floor like so,
Width * Length = Square Ft.
8.5 ft. * 5 ft. = 42.5 sq. ft.
Now that we have that, we can simply divide this number by the amount that each tile covers in order to find the amount of tiles needed to cover the entire floor.
42.5 sq ft. / 0.5 ft = 85 tiles.
So we now see that Rosanne will need a total of 85 tiles to cover the entire floor.