The girl bit doesn't really matter except for how it says 5/9 which shows that you should factor it by 3's. If you multiply both the 2 and the 3 in 2/3 you would clearly get 6/9. Which is the same thing but is to get it matching with how the question wrote about the people wearing glasses.
Answer: 6/9 people
4.5
6*-1=-6
-6/-4=1.5
1.5+3=4.5
I think it is -5.9. Sorry if I'm wrong.