JEE Mains · Maths · STD 12 - 13. probability
A box contains \(15\) green and \(10\) yellow balls. lf \(10\) balls are randomly drawn, one-by-one, with replacement, then the variance of the number of green balls drawn is :
- A \(\frac{6}{{25}}\)
- B \(\frac{{12}}{5}\)
- C \(6\)
- D \(4\)
Answer & Solution
Correct Answer
(B) \(\frac{{12}}{5}\)
Step-by-step Solution
Detailed explanation
(2) We can apply binomial probability distribution We have \(n=10\) \(\mathrm{p}=\) Probability of drawing a green ball \(=\frac{15}{25}=\frac{3}{5}\) Also \(q=1-\frac{3}{5}=\frac{2}{5}\) Variance = npq \(=10 \times \frac{3}{5} \times \frac{2}{5}=\frac{12}{5}\)
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