Five students are selected from 11. How many ways can these students be selected if two specified students are not selected? - Mathematics and Statistics

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Sum

Five students are selected from 11. How many ways can these students be selected if two specified students are not selected?

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Solution

Number of students = 11
Number of students to be selected = 5
Here, 2 specified students are not included.
So, we need to select 5 students from the remaining 9 students.
This can be done in:
= `""^9"C"_5`

= `(9 xx 8 xx 7 xx 6)/(4 xx 3 xx 2 xx 1)`

= 126 ways
Thus, 126 selections can be made such that 2 specified students are not included.

Concept: Combination
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Chapter 6: Permutations and Combinations - Exercise 6.7 [Page 90]

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Balbharati Mathematics and Statistics 2 (Commerce) 11th Standard HSC Maharashtra State Board
Chapter 6 Permutations and Combinations
Exercise 6.7 | Q 15. (b) | Page 90

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