Check sibling questions

Example 4 - Find number of different signals at least 2 flags

Example 4 - Chapter 7 Class 11 Permutations and Combinations - Part 2
Example 4 - Chapter 7 Class 11 Permutations and Combinations - Part 3
Example 4 - Chapter 7 Class 11 Permutations and Combinations - Part 4
Example 4 - Chapter 7 Class 11 Permutations and Combinations - Part 5
Example 4 - Chapter 7 Class 11 Permutations and Combinations - Part 6
Example 4 - Chapter 7 Class 11 Permutations and Combinations - Part 7

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Transcript

Example 4 Find the number of different signals that can be generated by arranging at least 2 flags in order (one below the other) on a vertical staff, if five different flags are available? A signal can have at least 2 flags i.e. flag can have 2 flags or 3 flags or 4 flags or 5 flags We need to calculate separately for each and then add For 2 flags Required number of signals = 5 × 4 = 20 First Flag Second Flag First Flag For 3 flags Required number of signals = 5 × 4 × 3 = 60 For 4 flags Required number of signals = 5 × 4 × 3 × 2 = 120 First Flag Second Flag Fourth Flag For 5 flags Required number of signals = 5 × 4 × 3 × 2 × 1 = 120 ways Thus, Hence, required number of signals = 320

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.