Vapor Pressure of a solution differs from pure solvent what's the difference

Know how the vapor pressure of a solution differs from that of pure solvent and be able to explain the difference.

This is a question in our review and I was wondering if anyone knows the answers, how are they different?

In a solution the vapor pressure of solvent is multiplied by the partial fraction of the solvent so lowered comparatively of pure solvent.
Patrial fraction of the solvent is given by (number of moles of solvent/(total number of moles in the solution)

The vapour pressure of pure solvent is more than the solution because in solution, because of solute molecules vapour pressure decreases.