document.write( "Question 725879: right now, susan's age is 4 years more than four times Jane's age. In 20 years, jane will be half of susan's age then. How old are they now? \n" ); document.write( "

Algebra.Com's Answer #444374 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+j+\"$ = Jane's age now
\n" ); document.write( "Let $\"+s+\"$ = Susan's age now
\n" ); document.write( " $\"+j+%2B+20+\"$ = Jane's age in 20 years
\n" ); document.write( " $\"+s+%2B+20+\"$ = Susan's age in 20 years
\n" ); document.write( "--------------------------------
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"+s+=+4j+%2B+4+\"$
\n" ); document.write( "(2) $\"+j+%2B+20+=+%281%2F2%29%2A%28+s+%2B+20+%29+\"$
\n" ); document.write( "----------------------------
\n" ); document.write( "(2) $\"+2%2A%28+j+%2B+20+%29+=+s+%2B+20+\"$
\n" ); document.write( "(2) $\"+2j+%2B+40+=+s+%2B+20+\"$
\n" ); document.write( "(2) $\"+s+=+2j+%2B+20+\"$
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+4j+%2B+4+=+2j+%2B+20+\"$
\n" ); document.write( "(2) $\"+2j+=+16+\"$
\n" ); document.write( "(2) $\"+j+=+8+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+s+=+4j+%2B+4+\"$
\n" ); document.write( "(1) $\"+s+=+4%2A8+%2B+4+\"$
\n" ); document.write( "(1) $\"+s+=+36+\"$
\n" ); document.write( "Jane is 8 and Susan is 36
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+j+%2B+20+=+%281%2F2%29%2A%28+s+%2B+20+%29+\"$
\n" ); document.write( "(2) $\"+8+%2B+20+=+%281%2F2%29%2A%28+36+%2B+20+%29+\"$
\n" ); document.write( "(2) $\"+28+=+56%2F2+\"$
\n" ); document.write( "(2) $\"+56+=+56+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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