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प्रश्न
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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उत्तर
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.
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