To find the rank of the word "SLOW" when all the permutations of the letters from the words "SLOW" and "FAST" are arranged in alphabetical order, we can follow these steps:
### Step 1: List the letters in alphabetical order
The letters of the words "SLOW" and "FAST" are S, L, O, W, F, A, T.
Arranging these letters alphabetically gives us:
A, F, L, O, S, T, W
### Step 2: Count the permutations before "SLOW"
We will count how many permutations come before the word "SLOW".
1. **Fix the first letter as 'A'**:
- Remaining letters: F, L, O, S, T, W
- Number of permutations = 6! = 720
2. **Fix the first letter as 'F'**:
- Remaining letters: A, L, O, S, T, W
- Number of permutations = 6! = 720
3. **Fix the first letter as 'L'**:
- Remaining letters: A, F, O, S, T, W
- Number of permutations = 6! = 720
4. **Fix the first letter as 'O'**:
- Remaining letters: A, F, L, S, T, W
- Number of permutations = 6! = 720
5. **Fix the first letter as 'S'**:
- Now we need to look at the second letter. The second letter in "SLOW" is 'L'.
- Before 'L', we can have:
- **Fix the second letter as 'A'**:
- Remaining letters: F, L, O, T, W
- Number of permutations = 5! = 120
- **Fix the second letter as 'F'**:
- Remaining letters: A, L, O, T, W
- Number of permutations = 5! = 120
6. **Fix the second letter as 'L'**:
- Now we need to look at the third letter. The third letter in "SLOW" is 'O'.
- Before 'O', we can have:
- **Fix the third letter as 'A'**:
- Remaining letters: F, L, T, W
- Number of permutations = 4! = 24
- **Fix the third letter as 'F'**:
- Remaining letters: A, L, T, W
- Number of permutations = 4! = 24
7. **Fix the third letter as 'O'**:
- Now we need to look at the fourth letter. The fourth letter in "SLOW" is 'W'.
- Before 'W', we can have:
- **Fix the fourth letter as 'A'**:
- Remaining letters: F, L, T
- Number of permutations = 3! = 6
- **Fix the fourth letter as 'F'**:
- Remaining letters: A, L, T
- Number of permutations = 3! = 6
- **Fix the fourth letter as 'L'**:
- Remaining letters: A, F, T
- Number of permutations = 3! = 6
### Step 3: Calculate the total permutations before "SLOW"
Now we sum all the permutations counted:
- For A: 720
- For F: 720
- For L: 720
- For O: 720
- For S with A: 120
- For S with F: 120
- For SL with A: 24
- For SL with F: 24
- For SLO with A: 6
- For SLO with F: 6
- For SLL with A: 6
Total = 720 + 720 + 720 + 720 + 120 + 120 + 24 + 24 + 6 + 6 + 6 = 2,586
### Step 4: Add 1 for the rank of "SLOW"
Since we want the rank of "SLOW", we add 1 to the total permutations before it:
Rank of SLOW = 2586 + 1 = 2587
### Final Answer
The rank of the word "SLOW" is **2587**.
---