Probability of Combined Events, terms

Sample space and favourable outcome come first, since probability itself is just favourable outcomes divided by the sample space. Once that's solid, learn to tell independent, dependent and mutually exclusive events apart, before using a tree diagram to combine probabilities across two or more events.

Independent and mutually exclusive events are confused constantly, even though they are almost opposites: independent events don't affect each other's probability and can happen together, while mutually exclusive events cannot happen at the same time at all. Dependent events, where one outcome changes the next probability, adds a third layer of confusion.

Expect instructions like "using a tree diagram, find the probability that…", "state whether events A and B are independent" or "find the probability of the complementary event". Many questions combine two events with "and" or "or", so knowing which rule to multiply or add is essential.