Hydrogen and oxygen combine to form H2O2 and H2O containing 5.93% and  11.2%  hydrogen respectively The data illustrates ;

In H2O2 :Mass ratio of H and O = 5.93 : 94.07mass of Oxygen combining with 1 gm (fixed) of H = 94.075.93 = 15.86 gm In H2O : Mass ratio of H and O = 11.2 : 88.8mass of oxygen combining with 1 gm (fixed) of H = 88.811.2 = 7.92Ratio of Oxygen combining with fixed mass of Hydrogen = 15.867.92 : 7.927.92 = 2 : 1This explains law of multiple proportions