\textbf{205.} Hypothetical element $X$ has two isotopes with masses $14\,\text{amu}$ and $16\,\text{amu}$, and an average atomic mass of $14.2\,\text{amu}$. The ratio of the number of atoms of the lighter isotope to the heavier isotope is:
$$
(1)\ \dfrac{1}{8} \hfill (2)\ \dfrac{1}{9} \hfill (3)\ \dfrac{1}{10} \hfill (4)\ \dfrac{1}{11}
$$
\medskip