Question

If P(not A) = 0.7, P(B) = 0.7 and P(B/A) = 0.5, then find P(A/B). 

Answer 1

\(P(\frac BA) = \frac{P(A \cap B)}{P(A)}\)

\(0.5 =\frac{P(A \cap B)}{0.3} \)

\(P(A \cap B) = 0.15\)

\(P(\frac AB) = \frac{P(A\cap B)}{P(B)} \)

\(=\frac{0.15}{0.7}\)

\(= 0.214\)

\(P(A \cup B) = 0.3 + 0.7 - 0.15 \)

\(= 0.85\)

Answer 2

= 0.3+ 0.7 -0.15 = 0.85