document.write( "Question 465452: today a man is 5 times the age of his son. in 15 years, the son will be 1/2 his fathers age. how old are they now? \n" ); document.write( "

Algebra.Com's Answer #318970 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"a\"$ = Father's age now
\n" ); document.write( "Let $\"b\"$ = Son's age now
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"+a+=+5b+\"$
\n" ); document.write( "(2) $\"+b+%2B+15+=+%281%2F2%29%2A%28+a+%2B+15+%29+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "(2) $\"+2%2A%28b+%2B+15%29+=+a+%2B+15+\"$
\n" ); document.write( "(2) $\"+2b+%2B+30+=+a+%2B+15+\"$
\n" ); document.write( "(2) $\"+a+-+2b+=+15+\"$
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+5b+-+2b+=+15+\"$
\n" ); document.write( "(2) $\"+3b+=+15+\"$
\n" ); document.write( "(2) $\"+b+=+5+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+a+=+5b+\"$
\n" ); document.write( "(1) $\"+a+=+25+\"$
\n" ); document.write( "25 is the Father's age now
\n" ); document.write( "5 is the Son's age now
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+b+%2B+15+=+%281%2F2%29%2A%28+a+%2B+15+%29+\"$
\n" ); document.write( "(2) $\"+5+%2B+15+=+%281%2F2%29%2A%28+25+%2B+15+%29+\"$
\n" ); document.write( "(2) $\"+20+=+%281%2F2%29%2A40+\"$
\n" ); document.write( "(2) $\"+40+=+40+\"$
\n" ); document.write( "OK \n" ); document.write( "

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