A $0\mathrm{.}4039g$ sample of p$-$cresol compound yields $1\mathrm{.}1518g$ and $0\mathrm{.}2694g$ in combustion analysis. Its molecular mass is $108\mathrm{.}1$ u$.$ For p$-$cresol, determine its

a$.$ empirical formula,

b$.$ molecular formula.