document.write( "Question 1088240: find the sum of all the integers between 100 and 500 and are divisble by 8
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Algebra.Com's Answer #702544 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "The multiples of 8 form an arithmetic sequence with common\r\n" );
document.write( "difference 8.  So d = 8\r\n" );
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document.write( "100/8 = 12.5\r\n" );
document.write( "The next whole number is 13, so the 13th multiple of 8, or \r\n" );
document.write( "13×8 = 104 is the smallest whole number divisible by 8 which \r\n" );
document.write( "is greater than 100. \r\n" );
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document.write( "500/8 = 62.6\r\n" );
document.write( "The previous whole number is 62, so the 62nd multiple of 8, or\r\n" );
document.write( "62×8 = 496 is the largest whole number divisible by 8 which is \r\n" );
document.write( "less than 500.\r\n" );
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document.write( "From the 13th to the 62nd multiple of 8 to the 62nd multiple\r\n" );
document.write( "of 8 is how many multiples of 8?\r\n" );
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document.write( "We can tell by subtracting 12 from both 13 and 60 to make the \r\n" );
document.write( "13th multiple of 8 the 1st one we are to consider. 12 subtracted \r\n" );
document.write( "from 62 is 50.  So there are 50 multiples of 8 in our sequence. \r\n" );
document.write( "So n=50\r\n" );
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document.write( "You can also find n this way:\r\n" );
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document.write( "a1 = 104 and an = 496\r\n" );
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document.write( "\"a%5Bn%5D=a%5B1%5D%2B%28n-1%29d\"\r\n" );
document.write( "\"496=104%2B%28n-1%298\"\r\n" );
document.write( "\"392=8%28n-1%29\"\r\n" );
document.write( "\"392=8n-8\"\r\n" );
document.write( "\"400=8n\"\r\n" );
document.write( "\"50=n\"\r\n" );
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document.write( "The formula for the sum is\r\n" );
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document.write( "\"S%5Bn%5D=expr%28n%2F2%29%28a%5B1%5D%2Ba%5Bn%5D%29\"\r\n" );
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document.write( "\"S%5B50%5D=expr%2850%2F2%29%28104%2B496%29\"\r\n" );
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document.write( "\"S%5B50%5D=25%28600%29\"\r\n" );
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document.write( "\"S%5B50%5D=15000\"\r\n" );
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document.write( "------------------\r\n" );
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document.write( "We solve:\r\n" );
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document.write( "\"matrix%281%2C3%2Cx%2F144%2C%22%22=%22%22%2C64%2Fx%29\"\r\n" );
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document.write( "\"matrix%281%2C3%2Cx%5E2%2C%22%22=%22%22%2C9216%29\"\r\n" );
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document.write( "\"matrix%281%2C3%2Cx%2C%22%22=%22%22%2Csqrt%289216%29%29\"\r\n" );
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document.write( "\"matrix%281%2C3%2Cx%2C%22%22=%22%22%2C96%29\"\r\n" );
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document.write( "So\r\n" );
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document.write( "Edwin
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