the total of the democratic and republican students is 98.
of those, 4 are republican women.
the ratio of republican women to democratic and republican students is 4/98.
the percent would be 4/98 * 100 = 4.08% rounded to 2 decimal places.
among the women in the class, the ratio of republicans to democrats is 4/20 * 100 = 400/20 = 20%.
if you make a table, your breakdown would look like this:
democrats republicans independents total
women 16 4 0 20
men 35 43 2 80
total 51 47 2 100
you would actually work your way back from the totals.
51 democrats, of which 16 are women, means that 35 democrats are men.
47 republicans, of which 4 are women, means that 43 republicans are men.
2 independents, of which 0 are women, means that 2 independents are men.