The original number is 34 . The sum of its digits is (3 + 4) = 7 . Reversing its digits makes it 43 . . . 9 more than 34.
How I did it: (There must be a much more elegant mathematical method)
There are only 6 possibilities for the original number. They are . . .
16 25 34 43 52 61 .
Instead of trying to dream up a sophisticated equation, I decided it was faster and easier to just go down the list and look for one that worked. The third one I tried worked.
