help please
4. There are 7 students in grade 11 and 15 students in grade 12 that are part of the VSS robotics club. A committee consisting of a president, vice president, media rep, and accountant is being chosen.

a. In how many ways could the panel be chosen if the president and vice president must be from different grades? [2A]

b. In how many ways could the panel be chosen if it must include at least one grade 11 student and at least one grade 12 student? [2A,1C