document.write( "Question 855484: The sum of ages of father and son is 36. If both live until the son becomes as old as his father is now, the sum of their ages becomes 84. Find their present ages. \n" ); document.write( "

Algebra.Com's Answer #515393 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+a+\"$ = father's age now
\n" ); document.write( "Let $\"+b+\"$ = Son's age now
\n" ); document.write( "-------------------------
\n" ); document.write( "(1) $\"+a+%2B+b+=+36+\"$
\n" ); document.write( "----------------------
\n" ); document.write( "Subtract $\"+2b+\"$ from both sides
\n" ); document.write( "(1) $\"+a+-+b+=+36+-+2b+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+a+=+36+-+b+\"$
\n" ); document.write( "When the Son's age is $\"+36+-+b+\"$ ( father's age now )
\n" ); document.write( "the difference in their ages will still be the same
\n" ); document.write( "( it never changes ), so
\n" ); document.write( " $\"+36+-+b+%2B+%28+36+-+b+%2B+%28+36+-+2b+%29+%29++=+84+\"$
\n" ); document.write( " $\"+36+-+b+%2B+36+-+b+%2B+36+-+2b+=+84+\"$
\n" ); document.write( " $\"+3%2A36+-+4b+=+84+\"$
\n" ); document.write( " $\"+108+-+4b+=+84+\"$
\n" ); document.write( " $\"+4b+=+108+-+84+\"$
\n" ); document.write( " $\"+4b+=+24+\"$
\n" ); document.write( " $\"+b+=+6+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+a+=+36+-+b+\"$
\n" ); document.write( "(1) $\"+a+=+30+\"$
\n" ); document.write( "The father is 30
\n" ); document.write( "The son is 6
\n" ); document.write( "---------------
\n" ); document.write( "check:
\n" ); document.write( "In 24 years, the son will be 30
\n" ); document.write( "In 24 years, the father will be 54
\n" ); document.write( " $\"+30+%2B+54+=+84+\"$
\n" ); document.write( "OK\r
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