In a box there are 3 red, 3 blue and 3 green balls. If 3 balls are picked from the box randomly, one by one, with replacement,
what is the probability that none of them will be blue?
6/9 = 2/3 chance of not blue on each pick
if replaced, then independent
2/3 * 2/3 * 2/3 = 8/27