Answer: 864 tiles
Explanation:
Rather than calculating the whole area of bathroom and area of one tile, It is quicker and easier to determine how many rows of tiles that will be needed.
Note that 1 feet = 12 inches
Each tile measures 3 inches on each side.
Length: 9 feet = 9 × 12 = 108 inches
Therefore, 108/3 = 36 tiles will fit along the length.
Width: 6 feet = 6 × 12 = 72 inches. Therefore, 72/3 = 24 tiles will fit along the width.
So, (36 × 24) = 864 tiles will be needed.