JEE Main 2017 · 2 Apr · Shift 1 · Mathematics Q85

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MathematicsSingle correct+4 / -1Question 85 of 90

A box contains 15 green and 10 yellow balls. If 10 balls are randomly drawn, one-by-one, with replacement, then the variance of the number of green balls drawn is :

\dfrac6{25}

\dfrac{12}5

Answer and worked solution

Official answer: D

The number of green balls is binomial with $n=10$ , $p=\frac35$ :
$\text{Var}=npq=10\cdot\frac35\cdot\frac25=\frac{12}5.$

Topics:Binomial distribution

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JEE Main 2017 · 2 Apr · Shift 1, Mathematics question 85