document.write( "Question 1091701: Tom is 2 years older than Sue and Bill is twice as old as Tom.
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Algebra.Com's Answer #706151 by Edwin McCravy(20059)\"\" \"About 
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>>Tom is 2 years older than Sue<<
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document.write( "T = S+2            <--first equation\r\n" );
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\n" ); document.write( ">>and Bill is twice as old as Tom.<<
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document.write( "B = 2T               <--second equation\r\n" );
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\n" ); document.write( ">>If you add all their ages and subtract 2, the sum is 20.<<
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document.write( "T + S + B - 2 = 20   <--third equation\r\n" );
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document.write( "Use the first equation to substitute (S+2) for T in the second equation.\r\n" );
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document.write( "B = 2(S+2)     <--fourth equation\r\n" );
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document.write( "Use the first equation to substitute S+2 for T in the third equation.\r\n" );
document.write( "Use the fourth equation to substitute 2(S+2) for B in the third equation\r\n" );
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document.write( "  T   + S +    B   - 2 = 20   <--third equation\r\n" );
document.write( "(S+2) + S + 2(S+2) - 2 = 20\r\n" );
document.write( "S + 2 + S + 2S + 4 - 2 = 20\r\n" );
document.write( "                4S + 4 = 20\r\n" );
document.write( "                    4S = 16\r\n" );
document.write( "                     S = 4, so Sue is 4 years old.\r\n" );
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document.write( "Substitute 4 for S in the first equation:\r\n" );
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document.write( "T = S+2            <--first equation\r\n" );
document.write( "T = 4+2\r\n" );
document.write( "T = 6, so Tom is 6 years old.\r\n" );
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document.write( "Substitute 6 for T in the second equation:\r\n" );
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document.write( "B = 2T             <--second equation\r\n" );
document.write( "B = 2(6)\r\n" );
document.write( "B = 12, so Bill is 12 years old.\r\n" );
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document.write( "Bill is 12 years old.\r\n" );
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document.write( "Edwin
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