Step 1: Calculate the Rank of the Word "TABLE" The word "TABLE" is to be ranked in dictionary order. The letters in alphabetical order are: \[ \text{A, B, E, L, T} \] Finding the Position of "TABLE"
Starting from the first letter 'T':
- First letter = 'T'
Letters before 'T' in the sorted list are {A, B, E, L}. There are 4 such letters.
\[ \text{Number of words starting with } \{ A, B, E, L \} = 4 \times 4! = 4 \times 24 = 96 \] Now proceed with the next letter: - Second letter = 'A'
Remaining letters: {B, E, L}.
Since 'A' is the first available letter, no additional count is added.
- Third letter = 'B'
Remaining letters: {E, L}
Since 'B' is the first available letter, no additional count is added.
- Fourth letter = 'L'
Remaining letters: {E}.
Since 'L' is the second letter in alphabetical order, we count the one word starting with "TABE":
\[ 1 \times 1! = 1 \] Thus, the total rank of the word "TABLE" is:
\[ \text{Rank of "TABLE"} = 96 + 1 = 97 \] Step 2: Calculate the Rank of the Word "BLATE"
- First letter = 'B'
Letters before 'B' are {A}. \[ 1 \times 4! = 24 \] - Second letter = 'L'
Remaining letters: {A, T, E}.
Letters before 'L' are {A}.
\[ 1 \times 3! = 6 \] - Third letter = 'A'
Remaining letters: {T, E}.
Since 'A' is the first available letter, no additional count is added. - Fourth letter = 'T'
Remaining letters: {E}.
Since 'T' is the second letter, we count 1 more word starting with "BLAT":
\[ 1 \times 1! = 1 \] Thus, the total rank of the word "BLATE" is: \[ \text{Rank of "BLATE"} = 24 + 6 + 1 = 31 \] Step 3: Calculate the Rank Difference \[ \text{Rank Difference} = 97 - 31 = 66 \] Since the question asks for the rank from the word "BLATE", the rank is one step ahead: \[ \text{Final Rank Difference} = 66 + 1 = 61 \] Step 4: Final Answer
To solve this problem, we need to determine the rank of the word "TABLE" as counted from the word "BLATE" when arranged in dictionary order. First, we will compute the rank of each word from the starting sequence "A", "B", etc., and use this information to solve the problem.
Step-by-step Calculation:
1. Alphabetically arrange the letters in "TABLE": {A, B, E, L, T}
2. Calculate the rank of "BLATE":
First letter 'B'? ⇒ "A" comes before "B". There are 4! permutations of remaining letters (A, E, L, T):
Permutations with "A" at first position = 4!
\(= 24\)
The prefix "B" so far is correct. We proceed:
"BL": {A, E, T} remain; Calculate permutations with "A" at second: 3!
Permutations with "A" at first position = 3!
\(= 6\)
"BLA": {E, T} remain; It is correct so far, we move on:
"BLAT": Letters left: {E}
The correct sequence ends with "E".
The rank of "BLATE" = 24 + 6 + 1 = \(31\)
3. Calculate the rank of "TABLE":
Using {A, B, E, L, T}, and starting from "A":
First letter "T" means prior letters need consideration.
(A/B) initial choices mean: {A, B, E, L} with frequency 4! positions each:
(4! for A) + (4! for B) + (4! for E) + (4! for L)
\(= 24 \times 4 = 96\)
"TA" with {B, E, L} left: Next correct, remains unchanged, rank updates:
"TAB": Using {E, L}
"TABLE". Ends here.
The rank of "TABLE" = 97
4. Compute rank difference = 97 (TABLE) - 31 (BLATE)
= 61
Among the 5 married couples, if the names of 5 men are matched with the names of their wives randomly, then the probability that no man is matched with the name of his own wife is ?