document.write( "Question 235938: In 17 years a father will be twice as old as his son, whose age at the present time is one third of his father's age. How old is the father now? \n" ); document.write( "

Algebra.Com's Answer #173802 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 present age
\n" ); document.write( ":
\n" ); document.write( "Write an equation for each statement:
\n" ); document.write( ":
\n" ); document.write( "\"In 17 years a father will be twice as old as his son,\"
\n" ); document.write( "f + 17 = 2(s + 17)
\n" ); document.write( "f + 17 = 2s + 34
\n" ); document.write( "f = 2s + 34 - 17
\n" ); document.write( "f = 2s + 17
\n" ); document.write( ":
\n" ); document.write( "\" whose age at the present time is one third of his father's age.\"
\n" ); document.write( "s = $\"1%2F3\"$ f
\n" ); document.write( "or we can say
\n" ); document.write( "f = 3s
\n" ); document.write( ":
\n" ); document.write( " How old is the father now?
\n" ); document.write( ";
\n" ); document.write( "Easy to find s first, replace f with 3s in the 1st equation
\n" ); document.write( "3s = 2s + 17
\n" ); document.write( "3s - 2s = 17
\n" ); document.write( "s = 17 yrs is son's present age
\n" ); document.write( "then
\n" ); document.write( "3(17) = 51 yrs is father's present
\n" ); document.write( ";
\n" ); document.write( ";
\n" ); document.write( "Check solution in the statement
\n" ); document.write( "In 17 years a father will be twice as old as his son,\"
\n" ); document.write( "51 + 17 = 2(17 + 17)
\n" ); document.write( "68 = 2(34) \n" ); document.write( "

\n" );