Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Probability

Question:

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

Options:

$\frac{1}{12}$

$\frac{1}{6}$

$\frac{1}{15}$

$\frac{1}{9}$

Correct Answer:

$\frac{1}{12}$

Explanation:

We have,

$ P(\overline{A} ∩B ∩ \overline{C})=\frac{1}{3}$

$⇒ P(( B ∩ \overline{C})∩  \overline{A})=\frac{1}{3}$

$⇒ P( B ∩ \overline{C})-P(( B ∩ \overline{C}) ∩ A = \frac{1}{3}$ $[∵ X ∩ \overline{Y}) = P(X) - P(X ∩ Y)]$

$⇒ P( B ∩ \overline{C}) - P(A ∩  B ∩ \overline{C})=\frac{1}{3}$

 $⇒ P( B ∩ \overline{C})-\frac{1}{3}=\frac{1}{3}$

$⇒ P( B ∩ \overline{C})=\frac{2}{3}$
 
$⇒P(B)- P( B ∩ C)=\frac{2}{3}$
 
$⇒P( B ∩ C) = P(B)-\frac{2}{3}=\frac{3}{4}-\frac{2}{3}=\frac{1}{12}$