How may committees of size 4 is to be selected from a group of 7 local students and 6 overseas students.

Answer 1

7+6=13 students.
choose 4 to make a committee.

Number of ways
= 13 choose 4
= C(13,4)
= (13,4)
=13!/(4!(13-4)!)
=13!/(4!9!)