How long in days is a mega second? hi, i'm my little brother with a maths assignment at the moment and i couldn't quite work out this question, i've had a lot of different answers and i can't determine which one is the correct answer?

Aprobability experiment is conducted in which the sample space of the experiment is s={7,8,9,10,11,12,13,14,15,16,17,18}, event f={7,8,9,10,11,12}, and event g={11,12,13,14}. assume that each outcome is equally likely. list the outcomes in f or g. find p(f or g) by counting the number of outcomes in f or g. determine p(f or g) using the general addition rule.