document.write( "Question 1156608: When bob was 12 his grandmother was 5 times of his age and minus 1/2 of his sister’s age (which was half of bob’s age). Now bob’s granny is 60. How old is bob now? \n" ); document.write( "

Algebra.Com's Answer #779353 by Edwin McCravy(20056) $\"\"$ $\"About$

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document.write( "When Bob was 12 \r\n" );
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document.write( "Suppose y years ago Bob was 12.  Then\r\n" );
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document.write( "B-y = 12\r\n" );
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document.write( "his grandmother was...\r\n" );
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document.write( "y years ago his grandmother was\r\n" );
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document.write( "G-y\r\n" );
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document.write( "5 times of his age and minus 1/2 of his sister’s age \r\n" );
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document.write( "G-y = 5(12)-1/2∙S\r\n" );
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document.write( "(which was half of bob’s age). \r\n" );
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document.write( "S = 1/2∙B\r\n" );
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document.write( "Now bob’s granny is 60. \r\n" );
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document.write( "G = 60\r\n" );
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document.write( "Solve the system:\r\n" );
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document.write( "From the 5th equation substitute 60 for G in the 2nd equation.\r\n" );
document.write( "Then from the 3rd equation, substitute (1/2)B for S in the 2nd\r\n" );
document.write( "equation.  \r\n" );
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document.write( "B=18, S=9, x=6\r\n" );
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document.write( "Edwin

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