If you don't think about it too much, it's pretty cool. Explanation:
- Any two digit number is represented as 10a+b, where a is the first digit and b is the second.
- The sum of the digits is obviously a+b
- Therefore, when you subtract the sum of the digits from the original number, your result is always 9a. In other words, it will always be nine times the first digit of the number you selected.
- Therefore, the mystic puzzle places the same symbol on all multiples of nine. Since one of them has to be the answer, it always "guesses" correctly.
The nice explanation by Uncle Scoopy misses one small point. Some of the multiples of nine, for example 90, do not share the same symbol as the rest. However, these multiples of nine cannot be reached by the procedure used in the Ghost Whisperer.
ReplyDeleteAlex Ambrioso