Solution
= Solution
Let $D$ denote detection. Weight each incident fraction by its <detection efficiency>, not by its loss <probability>. <Bayes' theorem> gives
$$
\boxed{P(H\mid D)=\frac{0.05(1-0.50)}{0.65(1-0.05)+0.30(1-0.20)+0.05(1-0.50)}
=\frac{10}{353}\simeq0.0283.}
$$
Thus about \b[2.83%] of detected particles are in the high-energy group. Energy-dependent <detector dead time> changes the composition of the observed sample.