There is one type of probability questions which are basically permutation-combination questions. So here I’ll talk about other types of probability questions that are not directly related to counting.
Q. A and B are two independent events. The probability of both occurring is 0.08. What is the probability that neither A nor B occurs given that A is twice as likely as B?
This is a straightforward question involving quadratic equations.
b2=0.04, b =0.2, a = 0.4.
So the answer is 1 – (a + b – ab) = 1 – (0.4 + 0.2 – 0.08) = 0.48