If 3 students are randomly chosen from a class of 30 to form a committee
(a) what is the total number of different committees that can be created?
Ans: Since order doesn't matter, use combination
$$C(30,3) = \frac{30!}{3!27!}$$
(b) If the first student chosen would be president, the second vice president, and the third be secretary, how many different ways can the committee be created?
Ans: Since order matter, use permutation
$$P(30,3) = C(30,3)\cdot 3!$$
Is the way I solved part (b) correct?