QJEEAdv08Ma60c8: JEE Advanced 2008 Mathematics - Class 11 JEEAdv08Ma60c8 Solution: Consider all possible permutations of the letters of the word…
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 5! |
| (C) | The number of permutations in which none of the letters D, L, N occurs in the last five positions is | (R) | 7 5! |
| (D) | The number of permutations in which the letters A, E, O occur only in odd positions is | (S) | 21 5! |
Multiple Choice Options
- A (A) - p ; (B) - s; (C) - q ; (D) - q
- B (A) - q ; (B) - q ; (C) - s ; (D) - p
- C (A) - p ; (B) - s; (C) - p ; (D) - r
- D (A) - p ; (B) - r ; (C) - q ; (D) - p
Step-by-Step Verified Solution
(A) Considering ENDEA as one group, remaining letters are N, O, E, L.
So, no. of permutations = 5!
(A) - (i)
(B) E occurs in 1st and last positions. The remaining letters are N, N, D, A, O, E, L.
No. of permutation
(B) - (iv)
(C) D, L, N should not occur in last five positions
D, L, N should occur in 1st four positions, but we have D, L, N, N.
So, ways of arranging D, L, N, N in 1st four positions
Ways of arranging remaining E, E, A, O, E in last five positions ,
Total
(C) - (iv)
(D) A, E, O occur in odd positions.
No. of odd positions = 5 and letters are E, E, E, A, O. i.e. 5
Ways of arranging those 5 letters in 5 odd positions
Remaining 4 letters D, L, N, N can be arranged in remaining 4 positions in ways
Total no. of permutations
(D) - (iii)