document.write( "Question 1119617: a lottery offers one $1000 prize, two $700 prizes, three $300 prizes, and four $200 prizes. \r
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\n" ); document.write( "\n" ); document.write( "One thousand tickets are sold at $6.00 each. \r
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\n" ); document.write( "\n" ); document.write( "Find the expectation if a person buys four tickets. \r
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\n" ); document.write( "\n" ); document.write( "Assume that the player's ticket is replaced after each draw and that the same ticket can win more than one prize. Round to two decimal places. question 12
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Algebra.Com's Answer #735232 by Theo(13342)\"\" \"About 
You can put this solution on YOUR website!
one prize worth 1000 dollars.
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\n" ); document.write( "three prizes worth 300 dollars each.
\n" ); document.write( "four prizes worth 200 dollars each.\r
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\n" ); document.write( "\n" ); document.write( "one thousand tickets sold at 6 dollars each.\r
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\n" ); document.write( "\n" ); document.write( "probability of winning 1000 dollars on a ticket is equal to 1/1000.
\n" ); document.write( "probability of winning 700 dollars on a ticket is equal to 2/1000.
\n" ); document.write( "probability of winning 300 dollars on a ticket is equal to 3/1000.
\n" ); document.write( "probability of winning 200 dollars on a ticket is equal to 4/1000.\r
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\n" ); document.write( "\n" ); document.write( "the expectation for that one ticket is therefore:\r
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\n" ); document.write( "\n" ); document.write( "1/1000 * 1000 + 2/1000 * 700 + 3/1000 * 300 + 4/1000 * 200 - 6.\r
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\n" ); document.write( "\n" ); document.write( "that is equal to -1.9 dollars.\r
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\n" ); document.write( "\n" ); document.write( "since the tickets can be reused, then each time the probability remains the same.\r
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\n" ); document.write( "\n" ); document.write( "his total probability is therefore 4 * -1.9 = -7.6 dollars.\r
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\n" ); document.write( "\n" ); document.write( "suppose that, for some reason, he bought all 1000 tickets.\r
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\n" ); document.write( "\n" ); document.write( "he's guaranteed to win all the prizes but he has to pay for all the tickets.\r
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\n" ); document.write( "\n" ); document.write( "he will gain 1000 + 2 * 700 + 3 * 300 + 4 * 100 = 4100, but he will lose
\n" ); document.write( "1000 * 6 = 6000 dollars.\r
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\n" ); document.write( "\n" ); document.write( "his expectation is therefore 4100 - 6000 = -1900.\r
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\n" ); document.write( "\n" ); document.write( "divide that by the 1000 tickets and the loss averages out to 1.9 dollars on each ticket.\r
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\n" ); document.write( "\n" ); document.write( "that would be his expectation on each ticket that he buys.\r
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\n" ); document.write( "\n" ); document.write( "he buys 4.\r
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\n" ); document.write( "\n" ); document.write( "4 * an average lose of 1.9 on each ticket means a total average loss of 7.6 dollars.\r
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\n" ); document.write( "\n" ); document.write( "if the tickets are not replaced on each draw, then the probabilities on each draw change.\r
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\n" ); document.write( "\n" ); document.write( "since they are replaced, the probabilities remain the same on each draw.\r
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\n" ); document.write( "\n" ); document.write( "i believe that's your answer.\r
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\n" ); document.write( "\n" ); document.write( "hopefully it's correct.\r
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\n" ); document.write( "\n" ); document.write( "if not, then let me know what the correct answer should be, since i haven't seen a problem like this one before.\r
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\n" ); document.write( "\n" ); document.write( "usually it's the expectation on one draw.\r
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\n" ); document.write( "\n" ); document.write( "replacing the ticket does keep the expectation on each draw the same, which is why i'm assuming the expectation is 4 * the expectatikon on 1 draw.\r
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