It’s hard to offer a revision sheet for probability because to some extent it’s different question to question but the most important thing to remember is consider probability questions carefully and logically then they aren’t too bad but getting your head around the question is the most important step. That said here a couple of general points and questions and answers can be found below:
- The probability of a condition happening is the number of outcomes that satisfy the condition divided by the total number of outcomes.
- The probability of A AND B happening is the probability of A happening MULTIPLIED by the probability of B happening.
- The probability of A OR B happening is the probability of A happening ADD the probability of B happening.
Now some examples: