document.write( "Question 1028740: A man is 45 years old. 12 years ago, he was three times as old as his daughter. How old is the daughter now? \n" ); document.write( "

Algebra.Com's Answer #643808 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+f+\"$ = father's age now
\n" ); document.write( "Let $\"+d+\"$ = daughter's age now
\n" ); document.write( "-----------------
\n" ); document.write( " $\"+f+=+45+\"$
\n" ); document.write( " $\"+f+-+12+=+3%2A%28+d+-+12+%29+\"$
\n" ); document.write( " $\"+45+-+12+=+3d+-+36+\"$
\n" ); document.write( " $\"+33+=+3d+-+36+\"$
\n" ); document.write( " $\"+11+=+d+-+12+\"$
\n" ); document.write( " $\"+d+=+23+\"$
\n" ); document.write( "The daughter is 23 now
\n" ); document.write( "---------------------
\n" ); document.write( "check:
\n" ); document.write( "12 yrs ago, the father was $\"+45+-+12+=+33+\"$
\n" ); document.write( "12 yrs ago the daughter was $\"+23+-+12+=+11+\"$
\n" ); document.write( "33 is 3 times 11
\n" ); document.write( "OK
\n" ); document.write( "Also note that the difference in their ages
\n" ); document.write( "never changes:
\n" ); document.write( " $\"+45+-+23+=+22+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+33+-+11+=+22+\"$ \n" ); document.write( "

\n" );