Chemistry question need an answer fast!!!!?

The problem states that N204(g)--->2NO2(g) at the equilibrium temperature of -40 degree celsius a .150 M sample of N2O4 undergoes a 0.456% decomposition. What is K and Kp? Please help me I have been stuck on this problem for hours and I need the answer with all the work HELP ME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!