Problem 3:
When 2 g of a gaseous substance A is introduced into an initially evacuated flask at 25°C,
the pressure is found to be 1 atm. 3 g of another gaseous substance B is then added to it at
the same temperature and pressure. The final pressure is found to be 1.5 atm. Assuming
ideal gas behaviour, calculate the ratio of the molecular weights of A and B.​