document.write( "Question 53377: Linae, the Kougra from Shenkuu, went shopping for Kou-jong tiles at the local toy shop the other day. The kou-jong tiles were on sale for only 28 Neopoints each. \r
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document.write( "However, she got it in her head that, for good luck, the total amount of Neopoints she must spend must be a number where all of the digits are the same. \r
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document.write( "With that in mind, what is the minimum number of tiles she must buy?\r
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document.write( "Please help, I cant figure this out!
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Algebra.Com's Answer #35666 by rapaljer(4671) You can put this solution on YOUR website! I think this is a really neat problem. Let x = number of tiles purchased. Then the total cost of the tiles would be 28x, which must be the same digit repeating. The total cost will be \n" ); document.write( "28x = k, or 28x = kk, or 28x = kkk, or 28x = kkkk, etc.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Therefore, you must find a number, such that \n" ); document.write( "x = k/28, or kk/28, or kkk/28, or kkkk/28, etc.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "This can also be written as \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The problem then is to find a number with repeating digits that is evenly divisible by 7 and 4. Moreover, since the number must also be divisible by 4, it means that the value of k must be 4 times the number 1 or 11 or 111 or 1111, where you are looking for the smallest such number that is divisible by 7. \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So try dividing 11/7, which does not go evenly.\r \n" ); document.write( "\n" ); document.write( "Try 111/7, which does not go evenly. \n" ); document.write( "Likewise continue with, 1111/7, 11111/7, 111111/7, etc. until you find a number that is divisible by 7. The latter \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The solution to the problem is 15873 tiles, whose cost is 15873*28 = 444444.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "R^2 at SCC \n" ); document.write( " |