Two element X atomic weight 75 and Y atomic weight 16 combine to give compound having 75.8% of X. The formula of the compound is

Elements	% composition	Atomic ratio	Simplest ratio
X	75.8%	$\frac{75.8}{75}=1.011$	$\frac{1.011}{1.011}=1$
Y	24.2%	$\frac{24.2}{16}=1.513$	$\frac{1.513}{1.011}=1.5or2$

So from this we found that the empirical formula of the compound is ${XY}_2$

Molecular formula of the compound = ${XY}_2$