Algebra.Com's Answer #852177 by ikleyn(52781)![\"\"](\"/images/stars/stars-13.gif\")  
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document.write( "The sum of two numbers is 21. Five times the first number added to 2 times the second number is 66. Find the numbers.
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document.write( " I will show here how to solve this problem MENTALLY, without using equations.\r
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document.write( "It is clear that we can re-formulate the problem  this way:\r\n" );
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document.write( " Two times the first number added to 2 times the second number is 42. \r\n" );
document.write( " Five times the first number added to 2 times the second number is 66. Find the numbers\r\n" );
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document.write( "Looking in these two lines, your brain may conclude that three times (3 = 5-2) the first number is \r\n" );
document.write( "the difference 66-42 = 24.\r\n" );
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document.write( "Hence, first number is 24/3 = 8.\r\n" );
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document.write( "Then the second number is 21-8 = 13.\r\n" );
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document.write( "ANSWER. First number is 8. Second number is 13.\r\n" );
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document.write( "Solved MENTALLY, without using equations.\r
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