To fill 12 vacancies there are 25 candidates of which 5 are from sceduled castes. If 3 of the vacancies are reserved for scheduled caste candidates while the rest are open to all, find the number of ways in which the selection can be made.

Asked by ashwinikumar59 | 6th Sep, 2010, 05:30: PM

Expert Answer:

Total candidates = 25 = 5 sc +20 openTotal vacancies = 12 =3sc +9openThere are 3 vacancies for sc, so choose 3 out of 5,No of ways = binomial_coefficient53=5!3!2!=10For 9 vacancies, there are 20 open candidates,so no of ways = binomial_coefficient209=20!9!11!Total no of ways = binomial_coefficient53binomial_coefficient209">

Answered by  | 7th Sep, 2010, 07:17: AM

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