Need a step-by-step solution for Q4, Q5, and Q6.

4. EventA occurs with probability 0.2. Event 3 occurs with probability 0.9. Events A and B: A. are disjoint. cannot be independent. B. C. are independent. D. cannot be disjoint. 5. I roll a fair six-sided die twice and obtain two numbers. [a] {8 points] Find the probability that "you observe a sum of 6\". [b] Find the probability that "you observe a number less than 3 at least once". People with type 0-negative blood are referred to as universal donors. Any patient can receive a transfusion ofO-negative red blood cells. Only 7% of the American population have O-negative blood. If 8 people appear at random to give blood, what is the probability that at least one of them is a universal donor