At 300 K, a sample of 3.0 g of gas A occupies the same volume as 0.2 g of hydrogen at 200 K at the same pressure. The molar mass of gas A is ____________ g mol^$-$1. (nearest integer) Assume that the behaviour of gases as ideal.

(Given : The molar mass of hydrogen (H₂) gas is 2.0 g mol^$-$1.)