find the least number of square tiles by which the floor of the room of dimension 20m by 15m can be covered completely

Answer 1

The room's floor has dimensions 20 m by 15 m and it is to be covered completely by square tiles, where each tile has l=w.

The common factor of 20 and 15 is 5, so a square tile 5x5 m has area 25m². The floor has area 20 x 15 m = 300m². 300 divided by 25 = 12 square tiles of size 5x5 m.

There will be 4 tiles going for the 20 m length and 3 tiles for the 15 m length. 4 x 3 = 12.