document.write( "Question 476970: John was twice as old as bob last year. In seven years john will be half again as bob. how old are they now? \n" ); document.write( "
Algebra.Com's Answer #327001 by josmiceli(19441)\"\" \"About 
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Let \"j\" = John's age now
\n" ); document.write( "Let \"b\" = Bob's age now
\n" ); document.write( "given:
\n" ); document.write( "(1) \"+j+-+1+=+2%2A%28+b+-+1+%29+\"
\n" ); document.write( "(2) \"+j+%2B+7+=+1.5%2A%28+b+%2B+7+%29+\"
\n" ); document.write( "Note that \"half again\" means 1.5 times
\n" ); document.write( "---------------------------------
\n" ); document.write( "(1) \"+j+-+1+=+2%2A%28+b+-+1+%29+\"
\n" ); document.write( "(1) \"+j+-+1+=+2b+-+2+\"
\n" ); document.write( "(1) \"+2b+-+j+=+1+\"
\n" ); document.write( "and
\n" ); document.write( "(2) \"+j+%2B+7+=+1.5%2A%28+b+%2B+7+%29+\"
\n" ); document.write( "(2) \"+j+%2B+7+=+1.5b+%2B+10.5+\"
\n" ); document.write( "(2) \"+-1.5b+%2B+j+=+3.5+\"
\n" ); document.write( "--------------------------
\n" ); document.write( "Add (1) and (2)
\n" ); document.write( "(1) \"+2b+-+j+=+1+\"
\n" ); document.write( "(2) \"+-1.5b+%2B+j+=+3.5+\"
\n" ); document.write( "\"+.5b+=+4.5+\"
\n" ); document.write( "\"+b+=+9+\"
\n" ); document.write( "Plug this result back into (1)
\n" ); document.write( "(1) \"+2b+-+j+=+1+\"
\n" ); document.write( "(1) \"+2%2A9+-+j+=+1+\"
\n" ); document.write( "(1) \"+j+=+18+-+1+\"
\n" ); document.write( "(1) \"+j+=+17+\"
\n" ); document.write( "John is 17 now and Bob is 9 now
\n" ); document.write( "check:
\n" ); document.write( "(2) \"+j+%2B+7+=+1.5%2A%28+b+%2B+7+%29+\"
\n" ); document.write( "(2) \"+17+%2B+7+=+1.5%2A%28+9+%2B+7+%29+\"
\n" ); document.write( "(2) \"+24+=+1.5%2A16+\"
\n" ); document.write( "(2) \"+24+=+24+\"
\n" ); document.write( "OK\r
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