a
\(\beta \,\, = \,\,\,{\text{50}}\,\,\,\,\therefore \,\,\,\,\beta \, = \,\,\frac{\alpha }{{1\,\, - \,\,\alpha }}\,\,\, \Rightarrow \,\,50\,\, = \,\,\frac{\alpha }{{1\,\,\, - \,\,\alpha }}\,\,\,\)

\( \Rightarrow \,\,50 - 50\,\,\alpha \,\, = \,\,\alpha \,\,\,\, \Rightarrow \,\,\,\alpha  = \,\,\frac{{50}}{{51}}\,\, = \,0.98\)