document.write( "Question 978480: Sarah is 2 times as old as Bob, 6 years ago Sarah was 4 times as old as Bob, how old is Bob now ? \n" ); document.write( "

Algebra.Com's Answer #599859 by Cromlix(4381) $\"\"$ $\"About$

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Hi there,
\n" ); document.write( "Sarah is 2 times as old as Bob,
\n" ); document.write( "S = 2B
\n" ); document.write( "6 years ago Sarah was 4 times as old as Bob
\n" ); document.write( "S - 6 = 4(B - 6)
\n" ); document.write( "Substitute 2B for S From first equation
\n" ); document.write( "2B - 6 = 4(B - 6)
\n" ); document.write( "Multiply out brackets
\n" ); document.write( "2B - 6 = 4B - 24
\n" ); document.write( "Collect like terms
\n" ); document.write( "2B - 4B = - 24 + 6
\n" ); document.write( "- 2B = - 18
\n" ); document.write( "B = -18/-2
\n" ); document.write( "B = 9
\n" ); document.write( "Therefore Bob is 9 yrs old at present
\n" ); document.write( "Hope this helps:-) \n" ); document.write( "

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