Find the number of different selections of 5 letters, which can be made from
`5A's,4B's,3C's,2D's and 1E`

Explanation

To solve the problem of finding the number of different selections of 5 letters from the given letters (5 A's, 4 B's, 3 C's, 2 D's, and 1 E), we can break it down into different cases based on the number of similar and different letters selected.

### Step-by-Step Solution:

1. **Case 1: All 5 letters are different.**
- The only letters available are A, B, C, D, and E.
- Since we can only select 5 letters and we have exactly 5 different letters, there is only 1 way to select them.
- Calculation: \( \binom{5}{5} = 1 \)
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