document.write( "Question 38570: How many 3 digit counting numbers are even? \n" ); document.write( "
Algebra.Com's Answer #24083 by AnlytcPhil(1806)\"\" \"About 
You can put this solution on YOUR website!
How many 3 digit counting numbers are even?\r\n" );
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document.write( "This is the arithmetic sequence\r\n" );
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document.write( "100, 102, 104, ··· , 998\r\n" );
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document.write( "an = a1 + (n-1)d\r\n" );
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document.write( "To find d:\r\n" );
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document.write( "d = 102 - 100 = 104 - 102 = 2\r\n" );
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document.write( "a1 = 100\r\n" );
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document.write( "an = 998\r\n" );
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document.write( "an = a1 + (n-1)d\r\n" );
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document.write( "998 = 100 + (n-1)(2)\r\n" );
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document.write( "998 = 100 + 2(n-1)\r\n" );
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document.write( "998 = 100 + 2n - 2\r\n" );
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document.write( "998 = 98 + 2n\r\n" );
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document.write( "900 = 2n\r\n" );
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document.write( "450 = n\r\n" );
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document.write( "So there are 450 three-digit counting numbers\r\n" );
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document.write( "Edwin\r\n" );
document.write( "AnlytcPhil@aol.com
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