document.write( "Question 705606: zelma is 18 years older than her son. She was three times as old as he was one year go. How old are they now \n" ); document.write( "

Algebra.Com's Answer #434645 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+z+\"$ = Zelma's age now
\n" ); document.write( "Let $\"+s+\"$ = her Son's age now
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"+z+=+s+%2B+18+\"$
\n" ); document.write( "(2) $\"+z+-+1+=+3%2A%28+s+-+1+%29+\"$
\n" ); document.write( "----------------------
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+s+%2B+18+-+1+=+3%2A%28+s+-+1+%29+\"$
\n" ); document.write( "(2) $\"+s+%2B+17+=+3s+-+3+\"$
\n" ); document.write( "(2) $\"+2s+=+20+\"$
\n" ); document.write( "(2) $\"+s+=+10+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+z+=+s+%2B+18+\"$
\n" ); document.write( "(1) $\"+z+=+10+%2B+18+\"$
\n" ); document.write( "(1) $\"+z+=+28+\"$
\n" ); document.write( "28 = Zelma's age now
\n" ); document.write( "10 = her Son's age now
\n" ); document.write( "--------------------
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+z+-+1+=+3%2A%28+s+-+1+%29+\"$
\n" ); document.write( "(2) $\"+28+-+1+=+3%2A%28+10+-+1+%29+\"$
\n" ); document.write( "(2) $\"+27+=+3%2A9+\"$
\n" ); document.write( "(2) $\"+27+=+27+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

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