Answer:
3.73 atm
Explanation:
Since there is no change in temperature, we use Boyle's law.
P₁V₁ = P₂V₂ where P₁ = initial pressure of Ar gas = unknown, P₂ = final pressure of Ar gas = 2.74 atm, V₁ = initial volume of Ar gas = 6.30 L and V₂ = final volume of Ar gas = 8.57 L
P₁ = P₂V₂/V₁ = 2.74 atm × 8.57 L/6.30 L = 3.73 atm