In how-many ways can a student choose a programme of 5 courses if 9 courses are available and 2 specific courses are compulsory for every student?

Explanation

Two course are compulsory out of 5 courses.
So we want to select 3 courses from `7(=9 -2)` courses.
It can be done in ` ^7 C_3` ways

`therefore` Number of ways `= ^7 C_3=7 !/4 ! 3 !=35` ways