There are 10 professors and 20 students out of whom a committee of 2 professors and 3 students is be formed. Find the number of ways in which this can be done. Further find in how many of these committees :
(i) A particular professor is included.
(ii) A particular student is included.
(iii) A particular student is excluded
In a college there are 20 professors including the principal and the vice principal. A committee of 5 is to be formed. In how many ways it can be formed so that neither the principal nor the vice principal is included?