If the letters of the word MATHS are permuted and in all possible words so formed are arranged as in a dictionary with serial numbers, then the serial number of the word THAMS is

Given word is MATHS.
In alphabetical order: A, H, M,S, T
Now, word starting with 
A_ _ _ _ _ _ i.e., 4!; H_ _ _ _ _ _ i.e., 4!
M_ _ _ _ _ _ i.e., 4!; S_ _ _ _ _ _ i.e., 4!
T A _ _ _ i.e., 3!; T H A M S i.e., 4!
Rank of the word THAMS =4 X 4!+1 X 3!+1=103