Question

In how many ways can 5 students be selected out of 11 students if
(a) 2 particular students are included?
(b) 2 particular students are not included?

Answer 1

Answer:

(a) 84

(b) 126

Step-by-step explanation:

Hi,

Given that a selection of 5 has to be made out of 11 students

(a) such that 2 particular student are included:

Since 2 particular students are included, remaining 3 students

should be selected from  the remaining 9 . This can be done in

⁹C₃ ways = 84

(b) If 2 particular students are not included, then 5 students

should be selected from  the remaining 5 which could be done

in ⁹C₅ ways = 126

Hope, it helps !