Finding Molecular Weight w/ freezing point depression

[roksteady22]

A compound contains 42.9% C, 2.4% H, and 38.1% O by mass. The addition of 3.16 grams of this compound to 75mL of cyclohexane(d=0.779g/mL) gives a solution with a freezing point of 0.0°C. The normal freezing point of cyclohexane is 6.50°C and its freezing point depression constant of 20.2°C/m. What is the molecular formula of the solute?

[kyle1990]