12 balls are distributed among 3 boxes, then the probability that the first box will contain 3 balls is

If the letters of the word REGULATIONS be arranged in such a way that relative positions of the letters of the word GULATIONS remain the same, then the probability that there are exactly 4 letters between R and E is

A random variable X has the probability distribution

For the events E = {X is a prime number} and F = {X < 4}, then P(E $$\cup$$ F) is

A die is tossed thrice. If event of getting an even number is a success, then the probability of getting at least 2 successes is