document.write( "Question 1121008: when the father was the same age as his daughter is now, she was 4 years old. when the daughter becomes the same age as her father is now, her father will be 79 years old. what are their ages \n" ); document.write( "

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\n" ); document.write( "when the father was the same age as his daughter is now, she was 4 years old. when the daughter becomes the same age as her father is now, her father will be 79 years old. what are their ages
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Let the daughter’s and father’s ages be D, and F, respectively
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document.write( "Then difference in ages = F – D
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document.write( "We then see that: D – (F – D) = 4_____D – F + D = 4____2D – F = 4_____F = 2D – 4 ---- eq (i)
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document.write( "Also, we see that F + (F – D) = 79_____2F – D = 79 ----- eq (ii)
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document.write( "2(2D – 4) – D = 79 ------- Substituting 2D – 4 for F in eq (ii)
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document.write( "4D – 8 – D = 79
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document.write( "4D – D = 79 + 8
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document.write( "3D = 87
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document.write( "D, or daughter is: 
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document.write( "Father’s age:  \n" );
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