Hey, any help would be appreciated. This is grade 12 math, so the simplest method would be easiest for me to understand. Thanks to anyone/everyone

#1) When is calculating the probability of an event more simply done by finding the probability of its complement? Provide an example and describe the method that would be used.

#2) Of 1200 students @ a highschool, 840 went to the athletic banquet and 460 went to the winter formal. If 'A' is the set of students that went to the athletic banquet and 'B' is the set of students who went to the formal, explain in words why these two sets cannot be disjoint.

#3) Marry Catherine takes a five-question True/False quiz on Probability Theory. What are the odds that she will get all the answers correct if she is only guessing but knows that her teacher puts more True than False questions on the quiz?