Final answer:
To calculate the number of three-letter words using the letters WXYZ with repetition allowed, you multiply the number of choices for each position (4 × 4 × 4), resulting in 64 possible words.
Step-by-step explanation:
When forming three-letter words with the letters WXYZ, and allowing for repetition, the number of possible combinations can be calculated using the Counting Principle. For each letter in the three-letter word, there are 4 choices (W, X, Y, or Z). Since repetition is allowed, we have 4 choices for the first letter, 4 choices for the second letter, and 4 choices for the third letter.
The total number of three-letter words can be found by multiplying the number of choices for each position: 4 × 4 × 4. This gives us a total of 64 possible words.