document.write( "Question 513480: selma is now 3 times as old as joyce. four years ago, selma was 4 times as old as joyce was then. find their present ages.
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Algebra.Com's Answer #344099 by Maths68(1474)\"\" \"About 
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Let
\n" ); document.write( "Present age of Selma = s
\n" ); document.write( "Present age of Joyce = j\r
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\n" ); document.write( "\n" ); document.write( "selma is now 3 times as old as joyce
\n" ); document.write( "s=3j........(1)
\n" ); document.write( "Four years ago,
\n" ); document.write( "s-4=j-4
\n" ); document.write( "then
\n" ); document.write( "Selma was 4 times as old as joyce
\n" ); document.write( "s-4=4(j-4)
\n" ); document.write( "s-4=4j-16
\n" ); document.write( "s=4j-16+4
\n" ); document.write( "s=4j-12.............(2)
\n" ); document.write( "Put the value of s in (2) from (1)
\n" ); document.write( "3j=4j-12
\n" ); document.write( "3j-4j=-12
\n" ); document.write( "-j=-12
\n" ); document.write( "Multiply by -1 both sides
\n" ); document.write( "j=12
\n" ); document.write( "Put the value of j in (1)
\n" ); document.write( "s=3j
\n" ); document.write( "s=3(12)
\n" ); document.write( "s=36\r
\n" ); document.write( "\n" ); document.write( "Present age of Selma = s = 36 years old
\n" ); document.write( "Present age of Joyce = j = 12 years old
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