\[\boxed{\mathbf{252.}}\]
\[x - количество\ элементарных\ \]
\[событий\ в\ опыте.\]
\[\textbf{а)}\ \frac{1}{3}x = 3\]
\[x = 3.\]
\[\textbf{б)}\ 0,1x = 1\]
\[x = 1\ :0,1\]
\[x = 10.\]
\[\textbf{в)}\ 0,125x = 1\]
\[x = \frac{1}{0,125} = \frac{1000}{125}\]
\[x = 8.\]
\[\textbf{г)}\ \frac{1}{k} \cdot x = 1\]
\[x = k.\]