document.write( "Question 892518: Five years ago a father was thrice as old as his son. Fifteen years hence he will be twice as old as his son find the present age of his son (in years) \n" ); document.write( "
Algebra.Com's Answer #540613 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
let f = father's present age
\n" ); document.write( "let s = son's age
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\n" ); document.write( "write an equation for each statement, simplify as much as possible.
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\n" ); document.write( " Five years ago a father was thrice as old as his son.
\n" ); document.write( "f - 5 = 3(s-5)
\n" ); document.write( "f - 5 = 3s - 15
\n" ); document.write( "f = 3s - 15 + 5
\n" ); document.write( "f = 3s - 10
\n" ); document.write( ":
\n" ); document.write( " Fifteen years hence he will be twice as old as his son find the present age of his son (in years)
\n" ); document.write( "f + 15 = 2(s + 15)
\n" ); document.write( "f + 15 = 2s + 30
\n" ); document.write( "f = 2s + 30 - 15
\n" ); document.write( "f = 2s + 15
\n" ); document.write( ":
\n" ); document.write( "f=f, therefore
\n" ); document.write( "3s - 10 = 2s + 15
\n" ); document.write( "3s - 2s = 15 + 10
\n" ); document.write( "s = 25 yrs is the son's age
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\n" ); document.write( "You can check this yourself, find the father's age and check both statements \n" ); document.write( "
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