document.write( "Question 886201: How many days will 1200 persons take to construct a bridge, if 450 persons can build the same in 45 days? \n" ); document.write( "
Algebra.Com's Answer #535770 by Edwin McCravy(20065)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Two ways to work it.\r\n" );
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document.write( "First way:\r\n" );
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document.write( "The LCM of 1200 persons and 450 persons is 3600 persons.\r\n" );
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document.write( "3600 persons is 3 times as many persons as 1200 persons and\r\n" );
document.write( "3600 persons is 8 times as many persons as 450 persons.\r\n" );
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document.write( "Since 450 persons can build 1 bridge in 45 days, then \r\n" );
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document.write( "3600 persons can build 8 bridges in 45 days.\r\n" );
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document.write( "So only 1200 persons will take 3 times as long or 135 days to build 8 bridges.\r\n" );
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document.write( "So to build only 1 bridge it will take 1200 persons only 1/8th as long,\r\n" );
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document.write( "1/8th of 135 days is 135/8 = \"16%267%2F8\" days.\r\n" );
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document.write( "Second way:\r\n" );
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document.write( "You can also use the worker-time-job formula, which is:\r\n" );
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document.write( "\"%28W%5B1%5DT%5B1%5D%29%2FJ%5B1%5D\"\"%22%22=%22%22\"\"%28W%5B2%5DT%5B2%5D%29%2FJ%5B2%5D\"\r\n" );
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document.write( "where\r\n" );
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document.write( "W1 = the number of workers in the first situation.\r\n" );
document.write( "T1 = the number of time units (days in this case) in the first situation.\r\n" );
document.write( "J1 = the number of jobs in the first situation.\r\n" );
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document.write( "W2 = the number of workers in the second situation.\r\n" );
document.write( "T2 = the number of time units (days in this case) in the second situation.\r\n" );
document.write( "J2 = the number of jobs in the second situation.\r\n" );
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document.write( "W1 = 1200             W2 = 450     \r\n" );
document.write( "T1 =  ? (unknown)     T2 = 45\r\n" );
document.write( "J1 =  1               J2 = 1\r\n" );
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document.write( "\"%28W%5B1%5DT%5B1%5D%29%2FJ%5B1%5D\"\"%22%22=%22%22\"\"%28W%5B2%5DT%5B2%5D%29%2FJ%5B2%5D\"\r\n" );
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document.write( "\"%281200%2AT%5B1%5D%29%2F1\"\"%22%22=%22%22\"\"%28450%2A45%29%2F1\"\r\n" );
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document.write( "\"1200%2AT%5B1%5D\"\"%22%22=%22%22\"\"20250\"\r\n" );
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document.write( "\"T%5B1%5D\"\"%22%22=%22%22\"\"20250%2F1200\"\r\n" );
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document.write( "Reduce that fraction by dividing numerator and\r\n" );
document.write( "denominator by 150\r\n" );
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document.write( "\"T%5B1%5D\"\"%22%22=%22%22\"\"135%2F8\"\r\n" );
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document.write( "\"T%5B1%5D\"\"%22%22=%22%22\"\"16%267%2F8\" days\r\n" );
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document.write( "Edwin
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