AIEEE 2002
JEE Main 2002 Mathematics question on Permutations and Combinations
The number of arrangements of the letters of the word BANANA in which the two N's do not appear adjacently, is
- A.
40
- B.
60
- C.
80
- D.
100
Show answer and solution
Correct option: A
Solution
Total arrangements of BANANA (3 A's, 2 N's, 1 B) = 6!/(3!·2!) = 60.
Arrangements where the 2 N's ARE adjacent: treat NN as one unit, giving 5 letters (NN, B, A, A, A) → 5!/3! = 20.
Non-adjacent arrangements = 60 - 20 = 40.
[AIEEE 2002]
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