Thermal Decomposition Pressure Calculation

For the thermal decomposition of N₂O₅(g) at constant volume, the following table can be formed, for the reaction mentioned below :
2N₂O₅(g) → 2N₂O₄(g) + O₂(g)

S.No.	Time/s	Total pressure / (atm)
1.	0	0.6
2.	100	'x'

x = ________ × 10^–3 atm [nearest integer]
Given : Rate constant for the reaction is 4.606 × 10^–2 s^–1.