Liquid A has vapor pressure \(x\), and liquid \(\mathrm{B}\) has vapor pressure \(y\). What is the mole fraction of the liquid mixture if the vapor above the solution is \(30 . \% \mathrm{~A}\) by moles? \(50 . \% \mathrm{~A}\) ? \(80 . \% \mathrm{~A}\) ? (Calculate in terms of \(x\) and \(y\).) What is the mole fraction of the vapor above the solution if the liquid mixture is \(30 . \%\) A by moles? \(50 . \%\) A? \(80 . \%\) A? (Calculate in terms of \(x\) and \(y\).)