document.write( "Question 550546: If two numbers chosen from [-2011, 2012] are multiplied, find the probability that their product is greater than zero. \n" ); document.write( "

Algebra.Com's Answer #358964 by Edwin McCravy(20063) $\"\"$ $\"About$

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document.write( "[-2011, 2012]\r\n" );
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document.write( "There are 2012 positive numbers, and 2011 negative numbers, and 1 zero.\r\n" );
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document.write( "So there are 2012+2011+1 or 4024 numbers to choose from.\r\n" );
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document.write( "We have to choose a pair of positive numbers or a pair of negative numbers.\r\n" );
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document.write( "If we choose the numbers with replacement:\r\n" );
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document.write( "P[(positive 1st AND positive 2nd) OR (negative 1st AND negative 2nd)] =\r\n" );
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document.write( "P(positive 1st)×P(positive 2nd) + P(negative 1st)×P(negative 2nd)\r\n" );
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document.write( "If the choosing of the numbers is done with replacement\r\n" );
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document.write( "× + ×\r\n" );
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document.write( "which works out to be  = .4997515528\r\n" );
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document.write( "If the choosing of the numbers is done without replacement\r\n" );
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document.write( "× + ×\r\n" );
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document.write( "which works out to be .4996272675\r\n" );
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document.write( "Edwin

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