Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Permutations and Combinations question

2008 · Shift 2 · Q39
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Advanced
  3. /Mathematics
  4. /Permutations and Combinations
  5. /2008 · Shift 2 · Q39

Permutations and Combinations question

2008 · Shift 2 · Q39

JEE AdvancedMathematicsPermutations and CombinationsMCQ+4 / −1

Consider all possible permutations of the letters of the word ENDEANOEL. Match the Statements/Expressions in Column I with the Statements/Expressions in Column II.

Column I Column II
(A) The number of permutations containing the word ENDEA is (P) 5!
(B) The number of permutations in which the letter E occurs in the first and the last position is (Q) 2 ×\times× 5!
(C) The number of permutations in which none of the letters D, L, N occurs in the last five positions is (R) 7 ×\times× 5!
(D) The number of permutations in which the letters A, E, O occur only in odd positions is (S) 21 ×\times× 5!

  1. A
    (A) - p ; (B) - s; (C) - q ; (D) - q
  2. B
    (A) - q ; (B) - q ; (C) - s ; (D) - p
  3. C
    (A) - p ; (B) - s; (C) - p ; (D) - r
  4. D
    (A) - p ; (B) - r ; (C) - q ; (D) - p
View written solutionFree

Correct answer: A

The given word is ENDEANOEL. We need to find the number of permutations based on different conditions.

First, let's analyze the letters in the word ENDEANOEL: Total number of letters = 9. The letters are: E (3 times), N (2 times), D (1 time), A (1 time), O (1 time), L (1 time).

Let's evaluate each statement in Column I.

(A) The number of permutations containing the word ENDEA is

  1. We can treat the word "ENDEA" as a single block or a single unit. Let's denote this block by (X).
  2. The letters used to form the block "ENDEA" are E, N, D, E, A. The original letters of ENDEANOEL are {E, E, E, N, N, D, A, O, L}.
  3. After forming the block, the remaining letters are {E, N, O, L}.
  4. We now need to arrange the 5 items: {(ENDEA), E, N, O, L}. These 5 items are all distinct.
  5. The number of permutations of these 5 distinct items is 5!5!5!.
  6. 5!=5×4×3×2×1=1205! = 5 \times 4 \times 3 \times 2 \times 1 = 1205!=5×4×3×2×1=120.
  7. This matches with (P) in Column II, which is 5!5!5!. Therefore, (A) -> (P).

(B) The number of permutations in which the letter E occurs in the first and the last position is

  1. The word has 9 positions. We fix the letter E at the first and the last positions. E _ _ _ _ _ _ _ E
  2. We have used two of the three E's. The remaining 7 letters are {E, N, N, D, A, O, L}.
  3. These 7 letters need to be arranged in the 7 middle positions.
  4. In this set of 7 letters, 'N' is repeated 2 times.
  5. The number of permutations is given by 7!2!=50402=2520\frac{7!}{2!} = \frac{5040}{2} = 25202!7!​=25040​=2520.
  6. We need to express this result in terms of 5!5!5! (5!=1205! = 1205!=120). 2520=21×120=21×5!2520 = 21 \times 120 = 21 \times 5!2520=21×120=21×5!.
  7. This matches with (S) in Column II, which is 21×5!21 \times 5!21×5!. Therefore, (B) -> (S).

(C) The number of permutations in which none of the letters D, L, N occurs in the last five positions is

  1. There are 9 positions in total. We can conceptually divide them into two sets: the first four positions and the last five positions.
  2. The letters specified are D, L, and N. In the word ENDEANOEL, we have D, L, N, N. These are 4 letters.
  3. The condition states that these 4 letters (D, L, N, N) cannot be in the last five positions. This implies they must occupy the first four positions.
  4. The remaining 5 letters are {E, E, E, A, O}. These letters must occupy the last five positions.
  5. First, let's find the number of ways to arrange {D, L, N, N} in the first four positions. Since 'N' is repeated twice, the number of ways is 4!2!=242=12\frac{4!}{2!} = \frac{24}{2} = 122!4!​=224​=12.
  6. Next, let's find the number of ways to arrange {E, E, E, A, O} in the last five positions. Since 'E' is repeated thrice, the number of ways is 5!3!=1206=20\frac{5!}{3!} = \frac{120}{6} = 203!5!​=6120​=20.
  7. The total number of such permutations is the product of these two values: 12×20=24012 \times 20 = 24012×20=240.
  8. Expressing 240 in terms of 5!5!5!: 240=2×120=2×5!240 = 2 \times 120 = 2 \times 5!240=2×120=2×5!.
  9. This matches with (Q) in Column II, which is 2×5!2 \times 5!2×5!. Therefore, (C) -> (Q).

(D) The number of permutations in which the letters A, E, O occur only in odd positions is

  1. In a 9-letter arrangement, there are 5 odd positions (1, 3, 5, 7, 9) and 4 even positions (2, 4, 6, 8).
  2. The letters A, E, O refer to all occurrences of these letters in the word. The set of vowels is {A, E, E, E, O}, which are 5 letters in total.
  3. The set of consonants is {N, N, D, L}, which are 4 letters in total.
  4. The condition requires that the 5 vowels {A, E, E, E, O} must be placed in the 5 odd positions.
  5. Consequently, the 4 consonants {N, N, D, L} must be placed in the 4 even positions.
  6. The number of ways to arrange the vowels in the 5 odd positions is 5!3!=1206=20\frac{5!}{3!} = \frac{120}{6} = 203!5!​=6120​=20 (since E is repeated 3 times).
  7. The number of ways to arrange the consonants in the 4 even positions is 4!2!=242=12\frac{4!}{2!} = \frac{24}{2} = 122!4!​=224​=12 (since N is repeated 2 times).
  8. The total number of such permutations is the product: 20×12=24020 \times 12 = 24020×12=240.
  9. Expressing 240 in terms of 5!5!5!: 240=2×120=2×5!240 = 2 \times 120 = 2 \times 5!240=2×120=2×5!.
  10. This matches with (Q) in Column II, which is 2×5!2 \times 5!2×5!. Therefore, (D) -> (Q).

Summary of Matches: (A) -> (P) (B) -> (S) (C) -> (Q) (D) -> (Q)

This corresponds to the option: (A) - p ; (B) - s; (C) - q ; (D) - q.

Previous

More from Permutations and Combinations

  • Let the set of all relations R on the set {a,b,c,d,e,f}, such that R is reflexive and symmetric, and R contains exactly 10 elements, be denoted by S. Then the number of elements in S is ​…2025 · Numerical
  • Let S be the set of all seven-digit numbers that can be formed using the digits 0,1 and 2. For example, 2210222 is in S, but 0210222 is NOT in S. Then the number of elements x in S such that at least one of the digits…2025 · Numerical
  • A group of 9 students, s1​,s2​,…,s9​, is to be divided to form three teams X,Y, and Z of sizes 2,3 , and 4 , respectively. Suppose that s1​ cannot be selected for the team X, and s2​ cannot be selected for the team…2024 · Numerical
  • Let S={1,2,3,4,5,6} and X be the set of all relations R from S to S that satisfy both the following properties: i. R has exactly 6 elements. ii. For each (a,b)∈R, we have ∣a−b∣≥2. Let Y={R∈X: The range of…2024 · Numerical
  • Let S={1,2,3,4,5,6} and X be the set of all relations R from S to S that satisfy both the following properties: i. R has exactly 6 elements. ii. For each (a,b)∈R, we have ∣a−b∣≥2. Let Y={R∈X: The range of…2024 · Numerical
  • The number of 4-digit integers in the closed interval [2022, 4482] formed by using the digits 0,2,3,4,6,7 is ​.2022 · Numerical
  • Consider 4 boxes, where each box contains 3 red balls and 2 blue balls. Assume that all 20 balls are distinct. In how many different ways can 10 balls be chosen from these 4 boxes so that from each box at least one red ball and one blue…2022 · MCQ
  • Let S1​={(i,j,k):i,j,k∈{1,2,....,10}}, S2​={(i,j):1≤i<j+2≤10,i,j∈{1,2,...,10}}, S3​={(i,j,k,l):1≤i<j<k<l,i,j,k,l∈{1,2,...,10}}…2021 · Multiple correct