WBJEE · Maths · Probability
\(A\) and \(B\) are two independent events such that \(P(A \cup B)=0.8\) and \(P(A)=0.3\). The \(P(B)\) is
- A \(\frac{2}{7}\)
- B \(\frac{2}{3}\)
- C \(\frac{3}{8}\)
- D \(\frac{1}{8}\)
Answer & Solution
Correct Answer
(A) \(\frac{2}{7}\)
Step-by-step Solution
Detailed explanation
Hints : Let \(\mathrm{P}(\mathrm{B})=x\) \[ \mathrm{P}(\mathrm{A} \cup \mathrm{B})=\mathrm{P}(\mathrm{A})+\mathrm{P}(\mathrm{B})-\mathrm{P}(\mathrm{A} \cap \mathrm{B})=0.3+(1-x)-0.3(1-x) \] or \(\quad 0.8=1-x+0.3 x\) or \(\quad 1-0.7 x=0.8\) or \(\quad 0.7 x=0.2\) or…
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