1. Class 11
2. Important Question for exams Class 11

Transcript

Ex7.3, 10 In how many of the distinct permutations of the letters in MISSISSIPPI do the four I’s not come together? Total number of permutation of 4I not coming together = Total permutation – total permutation of I coming together In MISSISSIPPI there are 4I, 4S, 2P and 1M Since letter are repeating we will use the formula = 𝑛!/𝑝1!𝑝2!𝑝3! Total number of alphabet = 11 Hence n = 11, there are 4I, 4S, 2P p1 = 4, p2 = 4, p3 = 2 Hence total number of permutation = 𝑛!/𝑝1!𝑝2!𝑝3! = 11!/4!4!2! = (11 × 10 × 9 × 8 × 7 × 6 × 5 × 4!)/((4 × 3 × 2 × 1)×(2 × 1)(4!)) = 34650 Now taking 4Is as one, MISSISSIPPI Here, there are repeating letters So, we use the formula , Number of permutation = 𝑛!/𝑝1!𝑝2! Number of letters = 8 Since there are 4 S & 2p p1 = 4, p2 = 2, Number of permutation with 4I together = 𝑛!/𝑝1!𝑝2! = 8!/4!2! = 840 Total number of permutation of 4I not coming together = Total permutation – total permutation of I coming together = 34650 – 840 = 33810

Important Question for exams Class 11