SOLUTION: Each apartment in a building is identified by 2 characters, 1 letter and 1 number. These consist of the letters A, B, C, and D and the numbers 1, 2, 3, and 4. How many unique apart

Question 1090857: Each apartment in a building is identified by 2 characters, 1 letter and 1 number. These consist of the letters A, B, C, and D and the numbers 1, 2, 3, and 4. How many unique apartments are possible given this identification arrangement?
Answer by ikleyn(52776) (Show Source): You can put this solution on YOUR website!
.
I assume that A1 is an allowable combination, but 1A is NOT allowable,
although the condition does not state it explicitly.

If so, then any combination (a character, a number) is allowable, and there are 4*4 = 16 such combinations.

The total number of such distinguishable combinations is 16, so 16 unique identification arrangements are possible.

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