To solve this problem, we can use the combined gas law, which states:
P₁V₁/T₁ = P₂V₂/T₂
where P₁ and T₁ are the initial pressure and temperature, P₂ and T₂ are the final pressure and temperature, and V₁ and V₂ are the initial and final volumes (assuming constant volume in this case since the container is rigid).
Let's plug in the values given:
P₁ = 320 torr
T₁ = 400 K
T₂ = 200 K
Since the volume is constant, V₁ = V₂, so we don't need to include it in the equation.
Now, we can solve for P₂:
P₁/T₁ = P₂/T₂
P₂ = (P₁ * T₂) / T₁
= (320 torr * 200 K) / 400 K
= 160 torr
Therefore, the pressure in the container at 200 K would be 160 torr (option a).