In higher oxide
Wt of metal= 0.8x80/100=0.64g
Wt. Of oxygen=0.8-0.64=0.16g
In lower Oxide
Wt. of metal will remain the same as in higher oxide=0.64g
wt. of oxygen =0.72-0.72=0.08g
The ratio of weight of oxygen which combines with a fixed weight of metal in two oxides is
As it is a whole number ratio . The law of multiple proportion is illustrated.