document.write( "Question 173634: \"I am 3 times as old as Sue is,\" Frank said to Ann. \"On the other hand, I am 15 years older than John, While Sue is 1 year younger than John. How old am I?\" \n" ); document.write( "

Algebra.Com's Answer #128501 by josmiceli(19441) $\"\"$ $\"About$

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Let Frank's age = $\"f\"$
\n" ); document.write( "Let Sue's age = $\"s\"$
\n" ); document.write( "Let John's age = $\"j\"$
\n" ); document.write( "Given is:
\n" ); document.write( "(1) $\"f+=+3s\"$
\n" ); document.write( "(2) $\"f+=+j+%2B+15\"$
\n" ); document.write( "(3) $\"s+=+j+-+1\"$
\n" ); document.write( "Substitute $\"f\"$ in (1) fro $\"f\"$ in (2)
\n" ); document.write( "(4) $\"3s+=+j+%2B+15\"$
\n" ); document.write( "Subtract (3) from (4)
\n" ); document.write( "(5) $\"2s+=+16\"$
\n" ); document.write( " $\"s+=+8\"$
\n" ); document.write( "Substitute this result in (1)
\n" ); document.write( " $\"f+=+3%2A8\"$
\n" ); document.write( " $\"f+=+24\"$
\n" ); document.write( "Now substitute $\"s\"$ in (3) to find $\"j\"$
\n" ); document.write( " $\"8+=+j+-+1\"$
\n" ); document.write( " $\"j+=+9\"$
\n" ); document.write( "Frank is 24 years old
\n" ); document.write( "check answer:
\n" ); document.write( "(1) $\"f+=+3s\"$
\n" ); document.write( " $\"24+=+3%2A8\"$
\n" ); document.write( " $\"24+=+24\"$
\n" ); document.write( "OK
\n" ); document.write( "(2) $\"f+=+j+%2B+15\"$
\n" ); document.write( " $\"24+=+9+%2B+15\"$
\n" ); document.write( " $\"24+=+24\"$
\n" ); document.write( "OK
\n" ); document.write( "(3) $\"s+=+j+-+1\"$
\n" ); document.write( " $\"8+=+9+-+1\"$
\n" ); document.write( " $\"8+=+8\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );