For the reaction: 2NO(g) + H2(g) → N2O(g) + H2O(g), the value of -dP/dt was found to be 1.5 Pa s^-1 — Chemical Kinetics Chemistry Question

Question

For the reaction: 2NO(g) + H2(g) → N2O(g) + H2O(g), the value of -dP/dt was found to be 1.5 Pa s^-1 for a pressure of 372 Pa for NO and 0.25 Pa s^-1 for a pressure of 152 Pa for NO, the pressure of H2 being constant. If pressure of NO was kept constant, the value of -dP/dt was found 1.60 Pa s^-1 for a pressure of 289 Pa for H2 and 0.79 Pa s^-1 for a pressure of 144 Pa for H2. If the order of reaction with respect to NO and H2 are a and b, respectively, then the value of (a + b) is