JEE Mains · Maths · STD 12 - 13. probability
The mean and variance of a binomial distribution are \(\alpha\) and \(\frac{\alpha}{3}\) respectively. If \(P(X=1)=\frac{4}{243}\), then \(P ( X =4\) or \(5)\) is equal to.
- A \(\frac{5}{9}\)
- B \(\frac{64}{81}\)
- C \(\frac{16}{27}\)
- D \(\frac{145}{243}\)
Answer & Solution
Correct Answer
(C) \(\frac{16}{27}\)
Step-by-step Solution
Detailed explanation
\(np =\alpha\) \(npq =\alpha / 3\) From \((1)\) and \((2)\) \(q =1 / 3\) and \(p =2 / 3\) \({ }^{n} C_{1} q^{n-1} p^{1}=\frac{4}{243}\) \(\frac{n}{3^{n}}=\frac{2}{243}\) \(n=6\) \(P (4\) or 5…
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