document.write( "Question 1198805: For Christmas, each member of a class sends the other classmates card. If 992 cards are exchanged, find the number of pupils in the class \n" ); document.write( "

Algebra.Com's Answer #832457 by ikleyn(52788) $\"\"$ $\"About$

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\n" ); document.write( "For Christmas, each member of a class sends the other classmates card.
\n" ); document.write( "If 992 cards are exchanged, find the number of pupils in the class
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document.write( "Let the number of members be n.\r\n" );
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document.write( "Then the number of cards is n*(n-1)   (each member sends (n-1) cards to other members).\r\n" );
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document.write( "Thus an equation to find n is\r\n" );
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document.write( "    n*(n-1) = 992.\r\n" );
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document.write( "From this equation\r\n" );
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document.write( "    n^2 -n - 992 = 0\r\n" );
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document.write( "    (n-32)*(n+31) = 0\r\n" );
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document.write( "    n = 32  or  n = -31, and we choose the positive root.\r\n" );
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document.write( "ANSWER.  There are 32 pupils in the class.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved.\r
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