document.write( "Question 1200352: A bag contains 3 gold marbles, 8 silver marbles, and 20 black marbles. Someone offers to play this game: You randomly select one marble from the bag. If it is gold, you win $3. If it is silver, you win $2. If it is black, you lose $1.\r
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Algebra.Com's Answer #834468 by ikleyn(52814) $\"\"$ $\"About$

You can put this solution on YOUR website!
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document.write( "Total marbles = 3 + 8 + 20 = 31.\r\n" );
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document.write( "The probability to get a gold   marble = .\r\n" );
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document.write( "The probability to get a silver marble = .\r\n" );
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document.write( "The probability to get a black  marble = .\r\n" );
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document.write( "Now write and evaluate the expression for the Math expectation\r\n" );
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document.write( "    E =  =  =   of a dollar.\r\n" );
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document.write( "ANSWER.  Math expectation is    of a dollar.\r\n" );
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document.write( "It is an infinitely long decimal, but it should not embarrass you: \r\n" );
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document.write( "    +----------------------------------------------------------------+\r\n" );
document.write( "    |   it is NOT what you win - it is only the MEAN VALUE to win    |\r\n" );
document.write( "    |        after playing this game infinitely many times,          |\r\n" );
document.write( "    |             so, it is an  \"abstract number\".                   |\r\n" );
document.write( "    +----------------------------------------------------------------+\r\n" );
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document.write( "If you want, you may round this value to the closest cent, but it is not necessary - \r\n" );
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document.write( "- it depends only on your wish or on the problem's requirement.\r\n" );
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document.write( "Since this problem wants the answer in dollars, you can round it to nearest cent.\r\n" );
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