50.0 mL of acetone (denisty @ 25 degrees Celsius=0.790 g/mL, M.W.=58.0 g/mol) is mixed with 150.0 mL of water (density @ 25 degrees Celsius=0.997 g/mL, M.W.=18.0 g/mol) at 25 degrees Celsius. If the vapor pressure of acetone at 25 degrees Celsius is 30.8 torr and the vapor pressure of water at 25 degrees Celsius is 22.0 torr, what is the vapor pressure of the mixture at 25 degrees Celsius?