Using the ideal gas law, PV = nRT. P = nRT/V = (2 mol × 0.0821 L·atm/mol·K × 540 K) / 44.8 L ≈ 1.98 atm. This is close to 2 atm. The answer key indicates 3 atm, which would be correct if T=546K and R=0.082, or if the temperature was 819K.