Answer:
If your tile is 16"x48" you will need to multiply them together.
16x48=768 square inches
There are 144 square inches in a square foot, so multiply 104 x 144 = 14,976
Finally take 14,976/768=19.5
You will need at least 20 tile to complete this. Likely with this size tile, you will have a lot of waste. Consider purchasing an additional 4 tile for waste, mistakes, and extra for an issue later.