Given a positive number N, when N is rounded by a certain method (for convenience, call it Method Y), the result is $$10^{n}$$ if and only if n is an integer and $$5 *10^{n-1} \leq N < 5*10^{n}$$. In a certain gas sample, there are, when rounded by Method Y, $$10^{21}$$ molecules of $$H_2$$ and also $$10^{21}$$ molecules of $$O_2$$. When rounded by Method Y, what is the combined number of $$H_2$$ and $$O_2$$ molecules in the gas sample ?
1.The number of $$H_2$$ molecules and the number of $$O_2$$ molecules are each less than 3 *$$10^{21}$$.
2.The number of $$H_2$$ molecules is more than mice the number of $$O_2$$ molecules.