At 345 K, the half life for the decomposition of a sample of a gaseous compound initially at 55.5 kP — Chemical Kinetics Chemistry Question

Question

At 345 K, the half life for the decomposition of a sample of a gaseous compound initially at 55.5 kPa was 340 s. When the pressure was 27.8, kPa the half life was found to be 170 s. The order of the reaction is ____. [integer answer]