Quick question about solutions?

A chemist needs to prepare 425 mL of a .315 M solution of NaOH from a 1.25 M solution of NaOH. How many mL of 1.25 M NaOH must be diluted with water to prepare the solution?

Thanks so much, and if you have anymore time it would be great if you could help me with these questions too:

Calculate the vapor pressure of a solution of 3.15 g of aspirin (C9H8O4) in a 75.0 g of methanol (CH3OH) at 21.2 degrees C. Pure methanol has a vapor pressure of 101 torr at this temperature. Aspirin is a non-volatile, non-electrolyte.

Salt is added to water and the mixture is stirred until no more salt dissolves. the salt that does not dissolve is allowed to settle out. What happens to the concentration of the salt in the solution if the water evaporates until the volume of the solution is half the original volume? (assume temperature is constant). Explain your answer.