\[\boxed{\mathbf{251.}}\]
\[\textbf{а)}\]
| \[Число\ орлов\] | \[0\] | \[1\] |
|---|---|---|
| \[Вероятность\] | \[0,5\] | \[0,5\] |
\[\textbf{б)}\]
| \[Число\ орлов\] | \[0\] | \[1\] | \[2\] |
|---|---|---|---|
| \[Вероятность\] | \[0,25\] | \[0,5\] | \[0,25\] |
\[\frac{1}{2} \cdot \frac{1}{2} = \frac{1}{4} = 0,25;\]
\[\frac{1}{2} \cdot \frac{1}{2} + \frac{1}{2} \cdot \frac{1}{2} = \frac{1}{4} + \frac{1}{4} = \frac{2}{4} = 0,5.\]
\[\textbf{в)}\ \]
| \[Число\ орлов\] | \[0\] | \[1\] | \[2\] | \[3\] |
|---|---|---|---|---|
| \[Вероятность\] | \[0,125\] | \[0,375\] | \[0,375\] | \[0,125\] |
\[\left( \frac{1}{2} \right)^{3} = \frac{1}{8} = 0,125;\]
\[\frac{1}{8} + \frac{1}{8} + \frac{1}{8} = \frac{3}{8} = 0,375.\]