<p>How many words can be formed using all the letters of the word <strong>ALLAHABAD</strong>?</p>
Step-by-Step Solution
Key Concept: ALLAHABAD has 9 letters with repetitions (A appears 4 times, L appears 2 times, H, B, D appear 1 time each). Use the formula for permutations with repetition: n!/(n₁!×n₂!×...×nₖ!) where nᵢ are frequencies of repeated elements.
**Step 1:** Count the total number of letters in the word ALLAHABAD.
The word ALLAHABAD contains $9$ letters.
**Step 2:** Identify the frequency of each distinct letter.
* The letter A appears $4$ times.
* The letter L appears $2$ times.
* The letter H appears $1$ time.
* The letter B appears $1$ time.
* The letter D appears $1$ time.
**Step 3:** Apply the formula for permutations with repetition.
The number of distinct words that can be formed using all the letters of a given word is calculated by the formula:
$$ \frac{n!}{n_1! n_2! \cdots n_k!} $$
where $n$ is the total number of letters, and $n_1, n_2, \ldots, n_k$ are the frequencies of the distinct letters.
Substituting the values for ALLAHABAD:
$$ \text{Number of words} = \frac{9!}{4! \times 2! \times 1! \times 1! \times 1!} $$
**Step 4:** Calculate the number of words.
$$ \text{Number of words} = \frac{362,880}{24 \times 2 \times 1 \times 1 \times 1} $$
$$ \text{Number of words} = \frac{362,880}{48} $$
$$ \text{Number of words} = 7,560 $$
Thus, $7,560$ distinct words can be formed using all the letters of the word ALLAHABAD.
Correct Answer: 1512