In how many ways can 4 letters be posted in 3 letter boxes?

Explanation

To solve the problem of how many ways 4 letters can be posted in 3 letter boxes, we can break it down step by step:

### Step-by-Step Solution:

1. **Identify the Variables**:
- We have 4 letters: L1, L2, L3, L4.
- We have 3 letter boxes: B1, B2, B3.

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