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If a box has 5 nickels, 10 dimes, and 25 quarters, and X is the amount of money collected after 20 draws WITHOUT replacement, what are $E(X)$ and $Var(X)$?

My thought process is that the total value of the box before any draws is 750, and the number of coins is 40, so the expected value of the first draw is 18.75, and perhaps with each successive draw we need to subtract 18.75 from the remaining value of the box.

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    I guess since we are drawing 20 times out of 40 coins, the expectation will just be the half the value of each coin, so it will be 5(.025)+10(.05)+25(.125)=3.75. Still stuck on how to calculate the variance. – 2017-01-30

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