The letters of the word RANDOM are written in all possible orders and ...
Step 1: Identify the letters and their order
The letters in "RANDOM" are A, D, M, N, O, R. Arranging them in alphabetical order gives us: A, D, M, N, O, R.
Step 2: Count the arrangements starting with letters before 'R'
1. Words starting with 'A':
- Remaining letters: D, M, N, O, R
- Number of arrangements = 5! = 120
2. Words starting with 'D':
- Remaining letters: A, M, N, O, R
- Number of arrangements = 5! = 120
3. Words starting with 'M':
- Remaining letters: A, D, N, O, R
- Number of arrangements = 5! = 120
4. Words starting with 'N':
- Remaining letters: A, D, M, O, R
- Number of arrangements = 5! = 120
5. Words starting with 'O':
- Remaining letters: A, D, M, N, R
- Number of arrangements = 5! = 120
Step 3: Count the arrangements starting with 'R'
Now we focus on words starting with 'R'.
1. Fix 'R' and consider the next letter:
- The next letter must be 'A' (the only letter before D, M, N, O):
- Remaining letters: D, M, N, O
2. Fix 'RA' and consider the next letter:
- The next letter can be 'D':
- Remaining letters: M, N, O
- Number of arrangements = 3! = 6
3. Fix 'RAD' and consider the next letter:
- The next letter can be 'M':
- Remaining letters: N, O
- Number of arrangements = 2! = 2
4. Fix 'RAM' and consider the next letter:
- The next letter can be 'N':
- Remaining letters: O
- Number of arrangements = 1! = 1
5. Fix 'RAN' and consider the next letter:
- The next letter must be 'D':
- Remaining letters: O, M
- Number of arrangements = 2! = 2
6. Fix 'RAND' and consider the next letter:
- The next letter must be 'O':
- Remaining letter: M
- Number of arrangements = 1! = 1
Step 4: Total the arrangements
Now we can sum all the arrangements:
- Words starting with 'A': 120
- Words starting with 'D': 120
- Words starting with 'M': 120
- Words starting with 'N': 120
- Words starting with 'O': 120
- Words starting with 'RA': 6
- Words starting with 'RAD': 2
- Words starting with 'RAM': 1
- Words starting with 'RAN': 2
- Words starting with 'RAND': 1
Total = 120 + 120 + 120 + 120 + 120 + 6 + 2 + 1 + 2 + 1 = 614
Conclusion
The rank of the word "RANDOM" is 614.