An isolated system consists of two perfectly sealed cuboidal compartments A and B separated by a movable rigid wall of cross-sectional area 0.1 m² as shown in the figure. Initially, the movable wall is held in place by latches L₁ and L₂ such that the volume of compartment A is 0.1 m³. Compartment A contains a monoatomic ideal gas at 5 bar and 400 K. Compartment B is perfectly evacuated and contains a massless Hookean spring of force constant 0.3 N m⁻¹ at its equilibrium length (stored elastic energy is zero). The latches L₁ and L₂ are released, the wall moves to the right by 0.2 m, where it is held at the new position by latches L₃ and L₄. Assume all the walls and latches are massless. The final equilibrium temperature, in K, of the gas in compartment A, rounded off to 1 decimal place, is _________