Chemical Kinetics

For the reaction 2N\(_2\)O\(_5\) \(\to\) 4NO\(_2\) + O\(_2\).

If initial pressure is 100 atm and rate constant \(k\) is 3.38 \(\times\) 10\(^{-5}\) s\(^{-1}\). after 20 min the final pressure of N\(_2\)O\(_5\) will be