Extremely good question. Let me give it a try.
First and foremost, we will try to identify the values of all the variables: T,M, and H
Firstly, the number is 19!. It has 5 appearing 3 times (5,10,15). So, it must end with three zeroes at the end.
Hence, the value of H must be 0.
Now, because 19! is 1*2*3*......*18*19, it is definitely divisible by 9.
Test of divisibility with 9 states that the sum of the digits must be a multiple of 9.
Thus, sum of the digits of 19! is 33 + T+M+H).
As, H = 0, we need 33 + (T+M) to be a multiple of 9.
So, T+M can be either 3 or 12 but nothing beyond it as maximum addition of T and M is 18.
Case 1: T+M = 3
Case 2: T+M = 12
Also, 19! is divisible by 11.
According to test of divisibility with 11, the difference between the sum of digits in odd places and sum of digits in even places must be a multiple of 11.
So,
Sum of digits at even places = 20+M
Sum of digits at odd places = 13+T
Case 3: 20+M - (13+T) = 7+M-T
M-T = 4 or M-T = -7
Now,
T+M = 3 and M-T = -7 does not lead to any solution for T and M
Also, T+M = 3 and M-T = 4 does not lead to any solution for T and M.
We can solve for T+M = 12 and M-T = 4
BUT
AS THERE IS ONLY ONE POSSIBILITY FOR T+M and Value of H is also known,
T+M+H = 12
Option C is our answer.
No need to check for the scenarios where T-M = 4 or T-M = -7 as again it will lead us to T+M = 12 as the only possible case.
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