document.write( "Question 760574: Gary is today 5 times as old as Joan. Two years later, he will be 4 times as old as Joan. How old is Joan today? \n" ); document.write( "

Algebra.Com's Answer #462725 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+g+\"$ = Gary's age now
\n" ); document.write( "Let $\"+j+\"$ = Joan's age now
\n" ); document.write( " $\"+g+%2B+2+\"$ = Gary's age in 2 years
\n" ); document.write( " $\"+j+%2B+2+\"$ = Joan's age in 2 years
\n" ); document.write( "----------------------------
\n" ); document.write( "(1) $\"+g+=+5j+\"$
\n" ); document.write( "(2) $\"+g+%2B+2+=+4%2A%28+j+%2B+2+%29+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "(2) $\"+g+%2B+2+=+4j+%2B+8+\"$
\n" ); document.write( "(2) $\"+g+=+4j+%2B+6+\"$
\n" ); document.write( "By substitution:
\n" ); document.write( "(2) $\"+5j+=+4j+%2B+6+\"$
\n" ); document.write( "(2) $\"+j+=+6+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+g+=+5j+\"$
\n" ); document.write( "(1) $\"+g+=+5%2A6+\"$
\n" ); document.write( "(1) $\"+g+=+30+\"$
\n" ); document.write( "Joan is 6 years old
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+g+%2B+2+=+4%2A%28+j+%2B+2+%29+\"$
\n" ); document.write( "(2) $\"+30+%2B+2+=+4%2A%28+6+%2B+2+%29+\"$
\n" ); document.write( "(2) $\"+32+=+4%2A8+\"$
\n" ); document.write( "(2) $\"+32+=+32+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

\n" );