40:10 is equivalent to 2:0.5 Think of it as a fraction. (40/10) We can then reduce that. So we divide 10 by 10 and what we do to one side we have to do to the other so we divide 40 by 10 and we get 4/1 we can then divide both sides by 2 and get 2/0.5 or 2:0.5 :D
