Cho \(P\left( A \right) = 0,2;P\left( B \right) = 0,51;P\left( {B|A} \right) = 0,8\). Tính \(P\left( {A|B} \right)\).
Ta có: \(P\left( {A|B} \right) = \frac{{P\left( {AB} \right)}}{{P\left( B \right)}} = \frac{{P\left( A \right).P\left( {B|A} \right)}}{{P\left( B \right)}} = \frac{{0,2.0,8}}{{0,51}} = \frac{{16}}{{51}}\)