document.write( "Question 1093381: On his last birthday, Grandfather claimed that he had lived 1/7 of his life as a boy, 1/12 as a teenager, 2/3 as a man and spent 9 years in old age. How old was Grandfather on his last birthday? \n" ); document.write( "

Algebra.Com's Answer #708013 by ikleyn(52788) $\"\"$ $\"About$

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document.write( "Let x be the Grandfather age.\r\n" );
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document.write( "Then you have this equation from the condition\r\n" );
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document.write( " = x.\r\n" );
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document.write( "Multiply both sides by 7*12 = 84 to rid of denominators\r\n" );
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document.write( "12x + 7x + 56x + 9*84 = 84x,\r\n" );
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document.write( "75x + 9*84 = 84x,\r\n" );
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document.write( "9*84 = 84x - 75x  ====>  9*84 = 9x  ====>  x = 84.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Answer. Grandfather was 84 years old.\r
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document.write( "          Notice that 7*12 = 84, therefore, one could suggest/guess the answer without calculations.\r\n" );
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\n" ); document.write( "\n" ); document.write( "To wider your horizon, there is very similar poetical mathematical legend from ancient times for the same theme and melody.\r
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\n" ); document.write( "\n" ); document.write( "http://mathworld.wolfram.com/DiophantussRiddle.html\r
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\n" ); document.write( "\n" ); document.write( "Also see these links in this forum\r
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\n" ); document.write( "\n" ); document.write( "https://www.algebra.com/algebra/homework/word/age/Age_Word_Problems.faq.question.244899.html\r
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\n" ); document.write( "\n" ); document.write( "https://www.algebra.com/algebra/homework/word/age/Age_Word_Problems.faq.question.427066.html\r
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