document.write( "Question 884192: A brother is 3years older than his sister,5years ago,the ratio of their ages was 4:3.find their present ages \n" ); document.write( "

Algebra.Com's Answer #534053 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+b+\"$ = brother's age now
\n" ); document.write( "Let $\"+s+\"$ = sister's age now
\n" ); document.write( "--------------------------
\n" ); document.write( "(1) $\"+b+=+s+%2B+3+\"$
\n" ); document.write( "(2) $\"+%28+b++-+5+%29+%2F+%28+s+-+5+%29+=+4%2F3+\"$
\n" ); document.write( "-----------------------------
\n" ); document.write( "(2) $\"+3%2A%28+b+-+5+%29+=+4%2A%28+s+-+5+%29+\"$
\n" ); document.write( "(2) $\"+3b+-+15+=+4s+-+20+\"$
\n" ); document.write( "(2) $\"+3b+-+4s+=+-5+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+b+-+s+=+3+\"$
\n" ); document.write( "Multiply both sides of (1) by $\"+3+\"$
\n" ); document.write( "and subtract (2) from (1)
\n" ); document.write( "(1) $\"+3b+-+3s+=+9+\"$
\n" ); document.write( "(2) $\"+-3b+%2B+4s+=+5+\"$
\n" ); document.write( "---------------------
\n" ); document.write( " $\"+s+=+14+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+b+=+s+%2B+3+\"$
\n" ); document.write( "(1) $\"+b+=+14+%2B+3+\"$
\n" ); document.write( "(1) $\"+b+=+17+\"$
\n" ); document.write( "The sister is 14 and the brother is 17
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+%28+17++-+5+%29+%2F+%28+14+-+5+%29+=+4%2F3+\"$
\n" ); document.write( "(2) $\"+12+%2F+9+=+4%2F3+\"$
\n" ); document.write( "(2) $\"+4%2F3+=+4%2F3+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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