To find the rank of the word "MUMBAI" when all its letters are arranged in alphabetical order, we can follow these steps:
### Step 1: Arrange the letters in alphabetical order
The letters of the word "MUMBAI" are A, B, I, M, M, U.
### Step 2: Calculate the total arrangements starting with letters before 'M'
1. **Words starting with 'A':**
- Remaining letters: B, I, M, M, U (5 letters)
- Total arrangements = 5! / 2! = 120 / 2 = 60 (since M is repeated)
2. **Words starting with 'B':**
- Remaining letters: A, I, M, M, U (5 letters)
- Total arrangements = 5! / 2! = 120 / 2 = 60
3. **Words starting with 'I':**
- Remaining letters: A, B, M, M, U (5 letters)
- Total arrangements = 5! / 2! = 120 / 2 = 60
Adding these gives:
- Total words before 'M': 60 + 60 + 60 = 180
### Step 3: Fix the first letter as 'M' and calculate for the second letter
Now we consider words starting with 'M'.
1. **Words starting with 'MA':**
- Remaining letters: B, I, M, U (4 letters)
- Total arrangements = 4! = 24
2. **Words starting with 'MB':**
- Remaining letters: A, I, M, U (4 letters)
- Total arrangements = 4! = 24
3. **Words starting with 'MI':**
- Remaining letters: A, B, M, U (4 letters)
- Total arrangements = 4! = 24
4. **Words starting with 'MM':**
- Remaining letters: A, B, I, U (4 letters)
- Total arrangements = 4! = 24
Adding these gives:
- Total words starting with 'M' before 'MUMBAI': 24 + 24 + 24 = 72
### Step 4: Fix the first two letters as 'MU' and calculate for the third letter
Now we consider words starting with 'MU'.
1. **Words starting with 'MUA':**
- Remaining letters: B, I, M (3 letters)
- Total arrangements = 3! = 6
2. **Words starting with 'MUB':**
- Remaining letters: A, I, M (3 letters)
- Total arrangements = 3! = 6
3. **Words starting with 'MUI':**
- Remaining letters: A, B, M (3 letters)
- Total arrangements = 3! = 6
4. **Words starting with 'MUM':**
- Remaining letters: A, B, I (3 letters)
- Total arrangements = 3! = 6
Now we need to fix 'MUM' and calculate for the fourth letter.
### Step 5: Fix the first three letters as 'MUM' and calculate for the fourth letter
Now we consider words starting with 'MUM'.
1. **Words starting with 'MUMA':**
- Remaining letters: B, I (2 letters)
- Total arrangements = 2! = 2
2. **Words starting with 'MUMB':**
- Remaining letters: A, I (2 letters)
- Total arrangements = 2! = 2
3. **Words starting with 'MUMI':**
- Remaining letters: A, B (2 letters)
- Total arrangements = 2! = 2
Finally, we reach 'MUMBAI'.
### Step 6: Calculate the rank
Now we sum all the arrangements calculated:
- Words before 'M': 180
- Words starting with 'MA', 'MB', 'MI', 'MM': 72
- Words starting with 'MUA', 'MUB', 'MUI', 'MUM': 6 + 6 + 6 + 6 = 24
- Words starting with 'MUMA': 2
- Words starting with 'MUMB': 2
- The word 'MUMBAI' itself counts as 1.
Adding these gives:
- Total rank = 180 + 72 + 24 + 2 + 2 + 1 = 281
Thus, the rank of the word 'MUMBAI' is **281**.