plseas help
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?

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?