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

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