Question

a class has 32 pupils 18 are boys the others are girls 12 pupil from this class went on trip one of these 12 pupils is chosen at random there is an even chance that the chosen pupil is a girl how many girls stayed in the class

Answer 1

Gather your facts
32 in class
18 boys in class
14girls in class

12 on trip
Half are girls 6 half are boys 6

So now that you organized your information how many girls are still in class room?
14-6=8