1 meter = 100 cm
Convert the dimensions of the room to cm:
30m x 100 = 3000 cm
24 m x 100 = 2400 cm
Area of floor = 3000 x 2400 = 7,200,000 square cm
Find number of tiles by dividing area of room by area of a tile:
7,200,00 / 9000 = 800
They will need 800 tiles
800 tiles / 10 tiles per carton = 80
They will need 80 cartons