document.write( "Question 628531: in two yrs a boy will be 3/4 as old as his sister.
\n" ); document.write( "two yrs ago he was 2/3 as old as she. how old are they? \n" ); document.write( "
Algebra.Com's Answer #395770 by ankor@dixie-net.com(22740)\"\" \"About 
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b = boy's present age
\n" ); document.write( "s = sister's present age
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\n" ); document.write( "\"in two yrs a boy will be 3/4 as old as his sister.\"
\n" ); document.write( "b + 2 = \"3%2F4\"(s+2)
\n" ); document.write( "multiply by 4 to get rid of the fraction
\n" ); document.write( "4(b+2) = 3(s+2)
\n" ); document.write( "4b + 8 = 3s + 6
\n" ); document.write( "4b = 3s + 6 - 8
\n" ); document.write( "4b = 3s - 2
\n" ); document.write( "4b - 3s = -2
\n" ); document.write( ":
\n" ); document.write( "\"two yrs ago he was 2/3 as old as she.\"
\n" ); document.write( "b - 2 = \"2%2F3\"(s-2)
\n" ); document.write( "multiply by 3
\n" ); document.write( "3(b-2) = 2(s-2)
\n" ); document.write( "3b - 6 = 2s - 4
\n" ); document.write( "3b = 2s - 4 + 6
\n" ); document.write( "3b - 2s = 2
\n" ); document.write( ":
\n" ); document.write( "Let use elimination here, multiply 1st equation by 2, the 2nd eq by 3
\n" ); document.write( "8b - 6s = -4
\n" ); document.write( "9b - 6s = 6
\n" ); document.write( "--------------subtraction eliminates s, find b
\n" ); document.write( "-b = -10
\n" ); document.write( "b = 10 yrs is the boys present age
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\n" ); document.write( "Find s: 3b - 2s = 2
\n" ); document.write( "3(10) - 2s = 2
\n" ); document.write( "30 - 2 = 2s
\n" ); document.write( "28 = 2s
\n" ); document.write( "s = 28/2
\n" ); document.write( "s = 14 yrs is the sister's present age
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\n" ); document.write( "You can check these solutions in the given statements.\r
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