Deepa was studying properties of gases. She took a flask and filled it with sulphur dioxide gas, and weighed it at temperature $$T$$ and pressure $$P$$. The weight of the flask containing the gas was found to be $$W_1$$. She then flushed the flask, cleaned and filled it with methane at the same temperature and pressure. The weight of the flask containing methane was found to be $$W_2$$. She repeated the process with oxygen under the same conditions and found the weight to be $$W_3$$. The ratio of the gas masses corresponding to $$W_1$$, $$W_2$$ and $$W_3$$ is