Please state the full question what percent of what DVD in her collection we dont have enough information to give you an answer, I will just list all the possible answers,
8+12+7+3 =30
Possible answers
Action = 8/30 = 26% or 27% depending if you are rounding
Comedy = 12/30 = 40%
Romance = 7/30 = 23%
Science Fiction = 3/30 = 10%