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Three rotten apples are mixed accidently with seven good apples and four apples are drawn one by one without replacement. Let the random variable X denote the number of rotten apples. If  and  2 represent mean and variance of X , respectively, then 10(  2 +  2 ) is equal to

1. 25
2. 250
3. 30
4. 20

Correct answer: 20

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