document.write( "Question 822831: Please help me solve this word problem
\n" ); document.write( "Quinn is twice as old as Karl and four years older than Parker the sum of their ages is 21. How old is Parker? Thank you! \n" ); document.write( "
Algebra.Com's Answer #495112 by Edwin McCravy(20056)\"\" \"About 
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Quinn is twice as old as Karl
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document.write( "            Q = 2K\r\n" );
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\n" ); document.write( "Quinn is ... four years older than Parker
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document.write( "            Q = P + 4\r\n" );
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\n" ); document.write( " the sum of their ages is 21.
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document.write( "    Q + K + P = 21\r\n" );
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document.write( "So we have this system of equations:\r\n" );
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document.write( "            Q = 2K\r\n" );
document.write( "            Q = P + 4\r\n" );
document.write( "    Q + K + P = 21\r\n" );
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document.write( "Substitute 2K for Q in the 2nd and 3rd equations:\r\n" );
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document.write( "           2K = P + 4\r\n" );
document.write( "   2K + K + P = 21\r\n" );
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document.write( "Simplify the second one\r\n" );
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document.write( "           2K = P + 4\r\n" );
document.write( "       3K + P = 21\r\n" );
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document.write( "Solve the first one for P\r\n" );
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document.write( "       2K - 4 = P\r\n" );
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document.write( "Substitute in 3K + P = 21\r\n" );
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document.write( "3K + (2K - 4) = 21\r\n" );
document.write( "  3K + 2K - 4 = 21\r\n" );
document.write( "           5K = 25\r\n" );
document.write( "            K = 5\r\n" );
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document.write( "Substitute 5 for K in 2K - 4 = P\r\n" );
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document.write( "     2(5) - 4 = P\r\n" );
document.write( "       10 - 4 = P\r\n" );
document.write( "            6 = P    <----answer!\r\n" );
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document.write( "Substitute  6 for P in Q = P + 4\r\n" );
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document.write( "            Q = 6 + 4\r\n" );
document.write( "            Q = 10\r\n" );
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document.write( "Checking:\r\n" );
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document.write( "Quinn, who is 10 is twice as old as Karl, who is 5, and Quinn, who is 10,\r\n" );
document.write( "is also four years older than Parker, who is 6. The sum of their ages is 21.\r\n" );
document.write( "Q + P + K = 10 + 6 + 5 = 21.\r\n" );
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document.write( "So it checks.\r\n" );
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document.write( "Edwin
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