document.write( "Question 126738: 11 years ago Hye was four times as old as her brother. In 1 year she will be twice as old as he is. What are their ages now? \n" ); document.write( "

Algebra.Com's Answer #92885 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"b\"$ = brother's age today
\n" ); document.write( "Let $\"h\"$ = her age today
\n" ); document.write( " $\"h+-+11+=+4%28b+-+11%29\"$
\n" ); document.write( " $\"h+%2B+1+=+2%28b+%2B+1%29\"$
\n" ); document.write( "------------------------
\n" ); document.write( " $\"h+-+11+=+4b+-+44\"$
\n" ); document.write( " $\"h+-+4b+=+-33\"$
\n" ); document.write( "------------------------
\n" ); document.write( " $\"h+%2B+1+=+2b+%2B+2\"$
\n" ); document.write( " $\"h+-+2b+=+1\"$
\n" ); document.write( "------------------------
\n" ); document.write( "So, now I have
\n" ); document.write( " $\"h+-+4b+=+-33\"$
\n" ); document.write( " $\"h+-+2b+=+1\"$
\n" ); document.write( "multiply the 2nd equation by $\"-1\"$ and add them
\n" ); document.write( " $\"h+-+4b+=+-33\"$
\n" ); document.write( " $\"-h+%2B+2b+=+-1\"$
\n" ); document.write( "------------------
\n" ); document.write( " $\"-2b+=+-34\"$
\n" ); document.write( " $\"b+=+17\"$
\n" ); document.write( " $\"h+-+2b+=+1\"$
\n" ); document.write( " $\"h+=+2b+%2B+1\"$
\n" ); document.write( " $\"h+=+2%2A17+%2B+1\"$
\n" ); document.write( " $\"h+=+35\"$
\n" ); document.write( "She is 35 and he is 17
\n" ); document.write( "check:
\n" ); document.write( " $\"h+-+11+=+4%28b+-+11%29\"$
\n" ); document.write( " $\"35+-+11+=+4%2817+-+11%29\"$
\n" ); document.write( " $\"24+=+24\"$
\n" ); document.write( "OK
\n" ); document.write( " $\"h+%2B+1+=+2%28b+%2B+1%29\"$
\n" ); document.write( " $\"35+%2B+1+=+2%2A18\"$
\n" ); document.write( " $\"36+=+36\"$
\n" ); document.write( "OK \n" ); document.write( "

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