where P1 and V1 are the initial pressure and volume and P2 and V2 are the final pressure and volume.

P1V1 = P2V2

(205 kPa)(4.00 L) = P2(12.0 L)

P2 = (205 kPa)(4.00 L) / (12.0 L)

P2 = 68.3 kPa

Therefore, the pressure in the container if the temperature remains constant is 68.3 kPa.