An aqueous solution of methanol in water has vapour pressure:

In an aqueous solution of methanol, both components are volatile. Methanol has a higher vapour pressure than water at a given temperature. According to Raoult's law, the total vapour pressure of the solution is the sum of the partial pressures of each component, which are proportional to their mole fractions. Since methanol's vapour pressure is higher than water's, adding methanol increases the total vapour pressure above that of pure water. Thus, the solution's vapour pressure is more than that of water.