document.write( "Question 829884: A father told to his daughter, \"when I was in your age, you were 4 years old, and when you are my age, I will be 88. What are their present ages? \n" ); document.write( "
Algebra.Com's Answer #500305 by math-vortex(648)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Hi, there--\r\n" );
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document.write( "THE PROBLEM:\r\n" );
document.write( "A father told to his daughter, \"when I was in your age, you were 4 years old, and when you are my age, I will be 88. What are their present ages?\r\n" );
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document.write( "A SOLUTION:\r\n" );
document.write( "Let F be the father's present age.\r\n" );
document.write( "Let D be the daughter's present age.\r\n" );
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document.write( "Some number of years ago, say k years ago, the father was D years old, and the daughter was \r\n" );
document.write( "4 years old. So,\r\n" );
document.write( "F - k = D\r\n" );
document.write( "D - k = 4\r\n" );
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document.write( "Combine these equations to give,\r\n" );
document.write( "F - D = D - 4\r\n" );
document.write( "F - 2D = - 4\r\n" );
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document.write( "In some number of years, say m years, the father will be 88 hers old, and the daughter will be\r\n" );
document.write( "F years old. So,\r\n" );
document.write( "F + m = 88\r\n" );
document.write( "D + m = F\r\n" );
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document.write( "Combine these equations to give,\r\n" );
document.write( "F - D = 88 - F\r\n" );
document.write( "2F - D = 88\r\n" );
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document.write( "Now we have two equations with two variables.\r\n" );
document.write( "F - 2D = -4\r\n" );
document.write( "2F - D = 88\r\n" );
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document.write( "Use the elimination method. Multiply each term in first equation by -2.\r\n" );
document.write( "-2F + 4D = 8\r\n" );
document.write( "  2F + -D = 88\r\n" );
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document.write( "3D = 96\r\n" );
document.write( "D = 32\r\n" );
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document.write( "The daughter is 32 years old. Substitute 32 for D in the first equation.\r\n" );
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document.write( "F - 2D = -4\r\n" );
document.write( "F - 2(32) = -4\r\n" );
document.write( "F = -4 + 64\r\n" );
document.write( "F = 60\r\n" );
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document.write( "The father is 60 years old and the daughter is 32 years old.\r\n" );
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document.write( "Hope this helps! Feel free to email if you have any questions about the solution.\r\n" );
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document.write( "Good luck with your math,\r\n" );
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document.write( "Mrs. F\r\n" );
document.write( "math.in.the.vortex@gmail.com\r\n" );
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