In how many of the distinct permutations of the letters in MISSISSIPPI do the four I’s not come together?
Solution:
We know that the number of arrangements (permutations) that can be made out of n things out of which there are p, q, r, ... number of repetitions = n! / [p! q! r! ...].
In the given word MISSISSIPPI,
No. of M's = 1
No. of I's = 4
No. of S's = 4
No. of P's = 2
Total number of letters = 11.
This, the total number of arrangements possible with the given alphabets = 11! / (4! 4! 2!) = 34,650.
If we consider all the four I's one unit, then we get
M, S, S, S, S, P, P, \(\fbox{IIII}\).
Then total number of units is 8 among which S is repeated 4 times and P is repeated twice.
Then the total number of arrangements (permutations) possible with the given alphabets = 8! / (4! 2!) = 840.
The distinct number of permutations of the letters in MISSISSIPPI that do not have the four I’s together = 34,650 - 840 = 33,810
NCERT Solutions Class 11 Maths Chapter 7 Exercise 7.3 Question 10
In how many of the distinct permutations of the letters in MISSISSIPPI do the four I’s not come together?
Summary:
The distinct number of permutations of the letters in MISSISSIPPI that do not have the four I’s together 33,810
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