Of the three independent events $\mathrm{E}_1, \mathrm{E}_2$ and $\mathrm{E}_3$, the probability that only $\mathrm{E}_1$ occurs is $\alpha$, only $\mathrm{E}_2$ occurs is $\beta$ and only $\mathrm{E}_3$ occurs is $\gamma$. Let the probability $p$ that none of events $\mathrm{E}_1, \mathrm{E}_2$ or $\mathrm{E}_3$ occurs satisfy the equations ( $\alpha -2 \beta) \mathrm{p}=\alpha \beta$ and $(\beta-3 \gamma) \mathrm{p}=2 \beta \gamma$. All the given probabilities are assumed to lie in the interval $(0,1)$. Then $\frac{\text { Probability of occurrence of } E_1}{\text { Probability of occurrence of } E_3}=$