Given a number K, let the last digit be "a". Thus we know that . This leads to the equation .Originally Posted byChuck_3000

Now, K must be a multiple of 14. Thus a can take on the values 0, 2, 4, 6, 8. Thus the only possible K values are 0, 7, 14, 21, 28. Of these only two are divisible by 14, so the answers are 14 and 28.

-Dan