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Digit Reversal Puzzle (Posted on 2015-07-27) Difficulty: 3 of 5
N is a 4-digit positive integer, whose last digit is not zero, and which does not contain any leading zeros. R(N) is the four-digit integer obtained by reversing the digits of N; for example, R(4386) = 6834

Determine all values of N that satisfy: R(N) = 4N + 3

No Solution Yet Submitted by K Sengupta    
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Solution a short explanation Comment 2 of 2 |

The 1st digits is clearly 1, forcing last digit to be 7.

Therefore we have to find x and y in the concatenation 1xy7.

 4ooo+400x+40y+28+3=7000+100y+10x+1

the above reduces to x=(99+2y)/13

solvable  in integers   only as   y=9 and  x=9


answer:  1997

My remark (at most d2) was flatly ignored.






Edited on July 27, 2015, 9:42 am
  Posted by Ady TZIDON on 2015-07-27 09:08:39

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