Question

5. A group contains a persons, the number of ways
of selecting 6 persons is equal to the number of
ways of selecting 9 persons peson the number of
ways of selecting four persons from the group is
​

Answer 1

Answer:

we know, number of ways of selecting r persons from n persons =

n

C

r

i.e.

n

C

5

=

n

C

8

but,

n

C

r

=

n

C

n−r

=> n=r+(n−r)

=> n=5+8

=> n=13