How many different 2 letter initials can be made using the letters d g m s and t if you can cause use letter only once in each initial?

The first initial can be any one of the 5 letters for each of those possibilities.

The second initial can be any one of the 4 remaining, unused letters.

Total number of different 2-letter initials is (5 x 4) = 20.

There's no information in the question that could help us guess what any of

the letters or initials stand for.