The answer is simple, divide 13.5 by 3, and divide 3 by itself.
13.5/3
=4.5
3/3
=1
Area Covered: 4.5 m^[2]. Paint: 1L.
Then multiply 4.5 by 10, all you have to do is move the decimal to the right to get:
Area Covered: 45 m^[2]. Paint: 10L.
Hope it helped.
