Question

if 2/3 of the girls in class have brown eyes and 1/4 of the girls have blue eyes, what fraction of the girls in class have neither blue or brown eyes.

Answer 1

1-(2/3+1/4)=
1-(8/12+3/12)
1-11/12
1/12

1/12 of girls the class has neither blue nor brown eyes.

You have to add the two fractions (2/3 and 1/4) together to get the fraction of the girls in the class that have blue or brown eyes and subtract that by one to get the fraction of the girls in the class that have neither brown nor blue eyes.

Hope this helps :)

Answer 2

2/3 + 1/4. You start by converting the fractions so that they have a common denominator.
8/12 + 3/12 = 11/12
11/12 of the girls have blue and brown eyes. That leaves 1/12 of the girls who have neither blue nor brown eyes.