document.write( "Question 388031: Four years ago, Lisa was twice as old as John. Four years from now, John will be three quarters of Lisa's age. How old is Lisa Now?
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Algebra.Com's Answer #274344 by Fombitz(32388) $\"\"$ $\"About$

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\"Four years ago, Lisa was twice as old as John\"
\n" ); document.write( " $\"L-4=2%28J-4%29\"$
\n" ); document.write( " $\"L-4=2J-8\"$
\n" ); document.write( "1. $\"L=2J-4\"$
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\n" ); document.write( "\"Four years from now, John will be three quarters of Lisa's age.\"
\n" ); document.write( " $\"J%2B4=%283%2F4%29%28L%2B4%29\"$
\n" ); document.write( " $\"4%28J%2B4%29=3%28L%2B4%29\"$
\n" ); document.write( " $\"4J%2B16=3L%2B12\"$
\n" ); document.write( "2. $\"4J=3L-4\"$
\n" ); document.write( "Substitute from eq. 1 into eq. 2,
\n" ); document.write( " $\"4J=3%282J-4%29-4\"$
\n" ); document.write( " $\"4J=6J-12-4\"$
\n" ); document.write( " $\"-2J=-16\"$
\n" ); document.write( " $\"highlight%28J=8%29\"$
\n" ); document.write( "Then from eq. 1,
\n" ); document.write( " $\"L=16-4\"$
\n" ); document.write( " $\"highlight%28L=12%29\"$
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\n" ); document.write( "Right now, Lisa is 12 and John is 8. \n" ); document.write( "

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