document.write( "Question 1027198: If (Mr. X + Mrs. Y = 69 years) and (Mr. X + Mr. Z = 72 years) and (Mrs. Y + Mr. Z = 79 years).\r
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Algebra.Com's Answer #642451 by ikleyn(52803) $\"\"$ $\"About$

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\n" ); document.write( "If (Mr. X + Mrs. Y = 69 years) and (Mr. X + Mr. Z = 72 years) and (Mrs. Y + Mr. Z = 79 years).\r
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document.write( "X + Y     = 69,      (1)\r\n" );
document.write( "X     + Z = 72,      (2)\r\n" );
document.write( "    Y + Z = 79.      (3)\r\n" );
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document.write( "Add the equations (1), (2) and (3). You will get\r\n" );
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document.write( "2X + 2Y + 2Z = 69 + 72 + 79 = 220,  \r\n" );
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document.write( "or\r\n" );
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document.write( "X + Y + Z = 110.     (4)\r\n" );
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document.write( "Now distract (1) from (4). You will get \r\n" );
document.write( "Z = 110 - 69 = 41.\r\n" );
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document.write( "Now distract (2) from (4). You will get \r\n" );
document.write( "Y = 110 - 72 = 38.\r\n" );
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document.write( "Now distract (3) from (4). You will get \r\n" );
document.write( "X = 110 - 79 = 31.\r\n" );
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document.write( "Answer. X = 31, Y = 38, Z = 41.\r\n" );
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\n" ); document.write( "\n" ); document.write( "For similar problems, see the lesson The tricks to solve some word problems with three and more unknowns using mental math in this site. \r
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