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document.write( "The hourly wage of some Toyota assembly line workers increased annually by the same percentage
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document.write( "if their wage went from 7.10 to 20.08 in 12 years what is the doubling time
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document.write( "According to the problem, for the annual salary we have this exponential equation\r\n" );
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document.write( " y =
, where \"t\" denotes years from the starting moment.\r\n" );
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document.write( "We want to find (1+r), the coefficient of growth.\r\n" );
document.write( "At t= 12 we have\r\n" );
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document.write( " 20.08 =
.\r\n" );
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document.write( "Divide both sides by 7.10\r\n" );
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=
, or\r\n" );
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document.write( " 2.828169014 =
.\r\n" );
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document.write( "Take logarithm base 10 of both sides\r\n" );
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document.write( " log(2.828169014) = 12*log(1+r)\r\n" );
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document.write( " log(1+r) =
= 0.037625447.\r\n" );
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document.write( "Hence,\r\n" );
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document.write( " 1+r =
= 1.09049944.\r\n" );
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document.write( "Thus we just found out the coefficient of growth.\r\n" );
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document.write( "To find the doubling period, we shoud find \"t\" from this equation\r\n" );
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document.write( " 2 =
, or\r\n" );
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document.write( " 2 =
.\r\n" );
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document.write( "Again, take logarithm base 10 of both sides\r\n" );
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document.write( " log(2) = t*log(1+r).\r\n" );
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document.write( "We just found out the value of log(1+r) above: it is 0.037625447.\r\n" );
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document.write( "Therefore, the doubling time is t =
= 8.000702 years,\r\n" );
document.write( "which we can round to 8 years.\r\n" );
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document.write( "ANSWER. The doubling period is 8 years.\r\n" );
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document.write( "Solved.\r
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