Example 15 - Chapter 6 Class 11 Permutations and Combinations
Last updated at Dec. 16, 2024 by Teachoo
Last updated at Dec. 16, 2024 by Teachoo
Example 15 In how many ways can 4 red, 3 yellow and 2 green discs be arranged in a row if the discs of the same colour are indistinguishable ? Total number of discs = 4 red + 3yellow + 2 green n = 9. Since color are repeating so we use this formula ๐!/๐1!๐2!๐3! Here n = 9 Out of 9 discs, 4 red, 3 yellow and 2 green & p1 = 4, p2 = 3, p3 = 2 The number of arrangement = ๐!/๐1!๐2!๐3! = 9!/(4! 3! 2!) = (9 ร 8 ร 7 ร 6 ร 5 ร 4!)/(4! ร (3 ร 2 ร 1)(2 ร 1)) = (9 ร 8 ร 7 ร 6 ร 5)/(3 ร 2 ร 2) = 1260. Hence, total number of arrangements is 1260
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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo