Question

Cho P(A) = \(\dfrac{2}{5}\); P(B | A) = \(\dfrac{1}{3}\); P(B | \(\overline{A}\)) = \(\dfrac{1}{4}\).

Giá trị P(B\(\overline{A}\)) là:

A. \(\dfrac{1}{7}\).                       B. \(\dfrac{4}{19}\).                      C. \(\dfrac{4}{21}\).                     D. \(\dfrac{3}{20}\).

Answer 1

\(P\left( {B\overline A } \right) = P\left( {\overline A } \right).P\left( {B|\overline A } \right) = \left( {1 - \frac{2}{5}} \right).\frac{1}{4} = \frac{3}{{20}}\)

Chọn D