document.write( "Question 851500: find the three digit number whose digits are in GP and and the digits of a number that is 400 smaller are in AP. \n" ); document.write( "
Algebra.Com's Answer #515718 by Edwin McCravy(20056)\"\" \"About 
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document.write( "Though three digit numbers with the same three digits are in GP and AP,\r\n" );
document.write( "once you subtract 400, the result will not have all digits the same.\r\n" );
document.write( "So we only consider three digit numbers with all three different digits.\r\n" );
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document.write( "The only three digit numbers with all different digits whose digits are \r\n" );
document.write( "in GP that we can subtract 400 from and get a positive number\r\n" );
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document.write( "421, 842, 931\r\n" );
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document.write( "421-400 = 21, not a three-digit number, so 421 is out\r\n" );
document.write( "842-400 = 442, 4,4,2 are not in AP, so 842 is out\r\n" );
document.write( "931-400 = 531, 5,3,1 are in AP with common difference -2.  \r\n" );
document.write( "So that's it!\r\n" );
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document.write( "Answer: 931\r\n" );
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document.write( "Edwin
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