document.write( "Question 510514: Zoron is ten years older than his sister. In three years, he will be twice as old as she will be then. How old are they now? \n" ); document.write( "

Algebra.Com's Answer #341828 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"z\"$ = Zoron's age now
\n" ); document.write( "Let $\"s\"$ = his sister's age now
\n" ); document.write( "given:
\n" ); document.write( " $\"+z+=+s+%2B+10+\"$
\n" ); document.write( " $\"+z+%2B+3++=+2%2A%28+s+%2B+3+%29+\"$
\n" ); document.write( "-------------------
\n" ); document.write( "By substitution:
\n" ); document.write( " $\"+s+%2B+10+%2B+3++=+2%2A%28+s+%2B+3+%29+\"$
\n" ); document.write( " $\"+s+%2B+13+=+2s+%2B+6+\"$
\n" ); document.write( " $\"+s+=+13+-+6+\"$
\n" ); document.write( " $\"+s+=+7+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+z+=+s+%2B+10+\"$
\n" ); document.write( " $\"+z+=+17+\"$
\n" ); document.write( "Zoron is 17 and his sister is 7
\n" ); document.write( "check:
\n" ); document.write( "In 3 years, he will be 20 and she will be 10
\n" ); document.write( "OK \n" ); document.write( "

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