document.write( "Question 344995: find the mean of all of the numbers from 1 to 1000 that end in 2 \r
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Algebra.Com's Answer #246816 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "We need to find their sum and the number of terms\r\n" );
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document.write( "The sum is\r\n" );
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document.write( "Sn = 2+12+22+32+42+52+62+72+82+92+102+ ... +972+982+992\r\n" );
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document.write( "This is an arithmetic series with \"a%5B1%5D=2\" and \"d=10\" and \"a%5Bn%5D=992\"\r\n" );
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document.write( "\"a%5Bn%5D=a%5B1%5D%2B%28n-1%29d\"\r\n" );
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document.write( "\"992+=+2+%2B+%28n-1%2910\"\r\n" );
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document.write( "\"992=2%2B10%28n-1%29\"\r\n" );
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document.write( "\"992=2%2B10n-10\"\r\n" );
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document.write( "\"992=10n-8\"\r\n" );
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document.write( "\"1000=10n\"\r\n" );
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document.write( "\"100=n\"\r\n" );
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document.write( "So there are 100 terms:\r\n" );
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document.write( "The sum formula is:\r\n" );
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document.write( "Sn = \"expr%28n%2F2%29%2A%28a%5B1%5D%2Ba%5Bn%5D%29\"\r\n" );
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document.write( "S100 = \"expr%28100%2F2%29%2A%282%2B992%29\"\r\n" );
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document.write( "S100 = \"50%2A%28994%29=49700\"\r\n" );
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document.write( "So the average term is their sum divided by 100, the number of terms\r\n" );
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document.write( "\"49700%2F100\" = 497.\r\n" );
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document.write( "Edwin
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