Answer:
10,000
Step-by-step explanation:
We can find the area of the floor in cm^2 and divide by the are of 1 tile in cm^2.
1 m = 100 cm
10 m = 1000 cm
40 m = 4000 cm
area of floor = LW = 1000 cm * 4000 cm = 4,000,000 cm^2
area of tile = s^2 = (20 cm)^2 = 400 cm^2
number of tiles = 4,000,000/400 = 10,000
Answer: 10,000 tiles