document.write( "Question 891254: 1,2,4,8,16,22,24,28...\r
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document.write( "where each number is the sum of the previous number and its final digit. How many numbers in the sequence are less than 1000? \n" );
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Algebra.Com's Answer #539637 by Edwin McCravy(20056)![]() ![]() You can put this solution on YOUR website! 1,2,4,8,16,22,24,28 \n" ); document.write( " \r\n" ); document.write( "Let's continue the pattern and get all the\r\n" ); document.write( "terms between 0 and 100.\r\n" ); document.write( "\r\n" ); document.write( "1, 2, 4, 8, 16, 22, 24, 28, 36, 42, 44,\r\n" ); document.write( "48, 56, 62, 64, 68, 76, 82, 84, 88, 96\r\n" ); document.write( "\r\n" ); document.write( "Except for the very first term of 1, notice in passing that the \r\n" ); document.write( "pattern of last digits goes 2,4,8,6 and continues repeating that\r\n" ); document.write( "sequence on and on. \r\n" ); document.write( "\r\n" ); document.write( "To get the next term after 96, we will add 6 to 96 and get 102, \r\n" ); document.write( "which ends in 02. Therefore, except for the very first term of 01, \r\n" ); document.write( "this pattern of 20 pairs of last two digits continues on and on. \r\n" ); document.write( "\r\n" ); document.write( "02, 04, 08, 16, 22, 24, 28, 36, 42, 44,\r\n" ); document.write( "48, 56, 62, 64, 68, 76, 82, 84, 88, 96\r\n" ); document.write( "\r\n" ); document.write( "So except for the 21 terms between 0 and 100,\r\n" ); document.write( "there are 20 between 100 and 200, 20 between\r\n" ); document.write( "200 and 300, and so on up to 20 between 900,and 1000.\r\n" ); document.write( "\r\n" ); document.write( "There are 10 groups of 100 less than 1000, and except\r\n" ); document.write( "for the first term 1, there are 20 terms between each\r\n" ); document.write( "two successive multiples of 100. So the answer is \r\n" ); document.write( "20×10 = 200 plus the very first term 1, which does \r\n" ); document.write( "not fit the pattern. Counting the 1 makes it 201.\r\n" ); document.write( "\r\n" ); document.write( "Answer: 201.\r\n" ); document.write( "\r\n" ); document.write( "Edwin\n" ); document.write( " |