Find the number between 1 and 49 (inclusive) such that the sum to the left of it is equal to the sum to the right of it.
Note: For example, between 1 and 8, 6 would be the answer, as the sum of the numbers to the left of 6, which is is equal to the sum of the numbers to the right of 6, which is
Bonus: Generalize it for any set of numbers from to with proof.