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← JEE Main 2022 · 28 Jul · Shift 2
MathematicsInteger+4 / -1Question 89 of 90

JEE Main 2022 · 28 Jul · Shift 2, Mathematics question 89

A bag contains 4 white and 6 black balls. Three balls are drawn at random from the bag. Let X be the number of white balls, among the drawn balls. If σ2\sigma^2 is the variance of X, then 100σ2100\sigma^2 is equal to ______.

Answer and worked solution

Official answer: 56

Hypergeometric. σ2=3⋅410⋅610⋅79=0.56\sigma^2=3\cdot\frac4{10}\cdot\frac6{10}\cdot\frac{7}{9}=0.56.

Answer: 56