An Alphabetical Collection!Discrete Mathematics Level 2
Each book from a library receives a label with 3 alphabets from A to Z as shown in the picture:
The first book receives the label AAA. The second book receives the label AAB and so on.
After the book AAZ, there are the books ABA, ABB, ABC and so on.
The last book of this library is the book DAB. How many books are there in this library?