document.write( "Question 487722: two years back a father was 3 times as old as his son.two years hence, twice the fathers age will equal to 5 times that of his son's age.what are their present ages? \n" ); document.write( "

Algebra.Com's Answer #333162 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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let f = father's present age
\n" ); document.write( "let s = son's present age
\n" ); document.write( ":
\n" ); document.write( "Write an equation and simplify it, for each statement
\n" ); document.write( ":
\n" ); document.write( "\"two years back a father was 3 times as old as his son.\"
\n" ); document.write( "f - 2 = 3(s - 2)
\n" ); document.write( "f - 2 = 3s - 6
\n" ); document.write( "f = 3s - 6 + 2
\n" ); document.write( "f = 3s - 4
\n" ); document.write( ":
\n" ); document.write( "\"two years hence, twice the fathers age will equal to 5 times that of his son's age.\"
\n" ); document.write( "2(f + 2) = 5(s + 2)
\n" ); document.write( "2f + 4 = 5s + 10
\n" ); document.write( "2f = 5s + 10 - 4
\n" ); document.write( "2f = 5s + 6
\n" ); document.write( ":
\n" ); document.write( "From the 1st equation we know f = (3s-4), replace f in the above equation
\n" ); document.write( "2(3s - 4) = 5s + 6
\n" ); document.write( "6s - 8 = 5s + 6
\n" ); document.write( "6s - 5s = 6 + 8
\n" ); document.write( "s = 14 yrs is son's present age
\n" ); document.write( "then
\n" ); document.write( "f = 3(14) - 4
\n" ); document.write( "f = 42 - 4
\n" ); document.write( "f = 38 yrs is father's present age
\n" ); document.write( ";
\n" ); document.write( ":
\n" ); document.write( "See if this works in the statement:
\n" ); document.write( "\"two years hence, twice the fathers age will equal to 5 times that of his son's age.\"
\n" ); document.write( "2(38+2) = 5(14+2)
\n" ); document.write( "2(40) = 5(16); confirms our solutions of f=38 and s=14 \n" ); document.write( "

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