For #6;
We know that there are 46% male students and 30% of them are seniors. This means that we have to assume that 30% of the male students are seniors and that 30% of the female students are seniors. Taking 30% of 46% gives us 13.8%.
For #7;
We are looking for the possibility that we choose a junior student (22%) or a sophomore student (28%). This adds up to 50% (22%+28% = 50%). That is out answer.
