document.write( "Question 322644: 1n 2005,a father was 4 times as old as his son.in the year 2015,thrice the son's age will exceed the father's age by ten years,in which year was the son born? \n" ); document.write( "
Algebra.Com's Answer #231093 by ankor@dixie-net.com(22740)\"\" \"About 
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1n 2005, a father was 4 times as old as his son.
\n" ); document.write( "In the year 2015,thrice the son's age will exceed the father's age by ten
\n" ); document.write( " years, in which year was the son born?
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\n" ); document.write( "In 2005, let; f = father's age, s = son's age:
\n" ); document.write( "f = 4s
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\n" ); document.write( "In 2015:
\n" ); document.write( "f + 10 = 3(s+10) - 10
\n" ); document.write( "f + 10 = 3s + 30 - 10
\n" ); document.write( "f + 10 = 3s + 20
\n" ); document.write( "f = 3s + 20 - 10
\n" ); document.write( "f = 3s + 10
\n" ); document.write( "Replace f with 4s, find s:
\n" ); document.write( "4s = 3s + 10
\n" ); document.write( "4s - 3s = 10
\n" ); document.write( "s = 10 yrs old in 2005
\n" ); document.write( "Son was born in 1995
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\n" ); document.write( "Check solution, fathers age in 2005, 4(10) = 40
\n" ); document.write( "In 10 yrs
\n" ); document.write( "40 + 10 = 3(10+10) - 10
\n" ); document.write( "50 = 3(20) - 10\r
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