If $P(B)=\frac{3}{4}, P(A ∩B ∩ \overline{C})=\frac{1}{3}$ and $ P(\overline{A} ∩B ∩ \overline{C})=\frac{1}{3}$, then $P(B ∩ C)$ is |
$\frac{1}{12}$ $\frac{1}{6}$ $\frac{1}{15}$ $\frac{1}{9}$ |
$\frac{1}{12}$ |
We have, $ P(\overline{A} ∩B ∩ \overline{C})=\frac{1}{3}$ $⇒ P(( B ∩ \overline{C})∩ \overline{A})=\frac{1}{3}$ $⇒ P( B ∩ \overline{C})-P(( B ∩ \overline{C}) ∩ A = \frac{1}{3}$ $[∵ X ∩ \overline{Y}) = P(X) - P(X ∩ Y)]$ $⇒ P( B ∩ \overline{C}) - P(A ∩ B ∩ \overline{C})=\frac{1}{3}$ $⇒ P( B ∩ \overline{C})-\frac{1}{3}=\frac{1}{3}$ $⇒ P( B ∩ \overline{C})=\frac{2}{3}$
$⇒P(B)- P( B ∩ C)=\frac{2}{3}$
$⇒P( B ∩ C) = P(B)-\frac{2}{3}=\frac{3}{4}-\frac{2}{3}=\frac{1}{12}$
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