My guess is questions like
marbles:
you have 2 red marbles and 8 white marbles.
if you pick 1, what's probability it will be red?
if you pick 2, what's probability both will be red?
if you pick 2, what probability it will be red first and white second?
if you pick 2, what's probability at least 1 will be red?
you have 1 red, 2 white, and 3 blue marbles.
if you pick 1, what's the probability it will be red or white?
deck of cards:
if you draw 2 cards, what's the probability of getting a pair?
if you draw 2 cards, what's the probability of getting two aces?
if you draw 2 cards, what's the probability of getting an ace or spade?
my suggestion would be to understand the concept behind these questions instead of memorizing the formulas. the questions can be easily rephrased so that the formula does not apply. i thinks there's an old ET thread with other interview questions.
