Question
Class 11MathematicsPermutations and Combinations

In how many of the distinct permutations of the letters in MISSISSIPPI do the four I’s not come together?

Verified Answer

In the given word MISSISSIPPI:

  • I appears 4 times
  • S appears 4 times
  • P appears 2 times
  • M appears once

Therefore, number of distinct permutations of the letters in the given word = (11!)/(4! × 4! × 2! × 1!) = 34650

Now, when the 4 I’s occur together, they are treated as a single object (IIII). This single object together with the remaining 7 objects will account for 8 objects.

These 8 objects in which there are 4 S’s and 2 P’s can be arranged in (8!)/(4! × 2! × 1! × 1!) = 840 ways.

Number of arrangements where all I’s occur together = 840

Thus, number of distinct permutations of the letters in MISSISSIPPI in which four I’s do not come together = 34650 − 840 = 33810