A mixture of ethanol and 1 -propanol behaves ideally at $36^{\circ} \mathrm{C}$ and is in equilibrium with its vapor. If the mole fraction of ethanol in the solution is $0.62$, calculate its mole fraction in the vapor phase at this temperature. (The vapor pressures of pure ethanol and 1-propanol at $36^{\circ} \mathrm{C}$ are $108 \mathrm{mmHg}$ and $40.0 \mathrm{mmHg}$, respectivelv.)