document.write( "Question 208974: When I am as old as my father is now, I will five times as old as my son is now. By then, my son will be eight years older than I am now. The sum of my father's age and my age is 100 years. How much older am I than my son? \n" ); document.write( "
Algebra.Com's Answer #158118 by ankor@dixie-net.com(22740)\"\" \"About 
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When I am as old as my father is now, I will five times as old as my son is now. By then, my son will be eight years older than I am now. The sum of my father's age and my age is 100 years. How much older am I than my son?
\n" ); document.write( ":
\n" ); document.write( "m = my age now
\n" ); document.write( "f = father's age now
\n" ); document.write( "s = son's age now
\n" ); document.write( "d = f - m; (me and dad's age difference)
\n" ); document.write( ":
\n" ); document.write( "\"When I am as old as my father is now, I will five times as old as my son is now.\"
\n" ); document.write( "father now is 5 times son now
\n" ); document.write( "f = 5s
\n" ); document.write( "we can substitute 5s for f and we have difference of
\n" ); document.write( "d = 5s - m
\n" ); document.write( ":
\n" ); document.write( "\"By then, my son will be eight years older than I am now.\"
\n" ); document.write( " (s + d) = m + 8
\n" ); document.write( "Substitute (5s-m) for d
\n" ); document.write( "s + (5s - m) = m + 8
\n" ); document.write( "6s - m - m = 8
\n" ); document.write( "6s - 2m = 8
\n" ); document.write( ":
\n" ); document.write( "\"The sum of my father's age and my age is 100 years.\"
\n" ); document.write( "f + m = 100
\n" ); document.write( "Substitute 5s for f
\n" ); document.write( "5s + m = 100
\n" ); document.write( "Multiply this equation by 2 and add to eq: 6s - 2m = 8
\n" ); document.write( "10s + 2m = 200
\n" ); document.write( " 6s - 2m = 8
\n" ); document.write( "----------------adding eliminates m, find s
\n" ); document.write( "16s = 208
\n" ); document.write( "s = \"208%2F16\"
\n" ); document.write( "s = 13 yrs is son's present age
\n" ); document.write( "then
\n" ); document.write( "5(13) = 65 yrs is father's present age
\n" ); document.write( ":
\n" ); document.write( "It's easy to find my age
\n" ); document.write( "65 + m = 100
\n" ); document.write( "m = 35 yrs is my age
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\n" ); document.write( ";
\n" ); document.write( "Check solutions in the statement: (d = 65 - 35 = 30 yrs difference)
\n" ); document.write( "\"By then, my son will be eight years older than I am now.\"
\n" ); document.write( "13 + 30 = 35 + 8
\n" ); document.write( ":
\n" ); document.write( "Dad: 65, me 35, son 13 \n" ); document.write( "
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