Hi teacher, can you help me with those questions?

For task 1, I only need help with question (c). I already have the answer but I need more explanation for the answer. so I can understand more.

Task 2: All athletes at the Olympic games are tested for performance-enhancing steroid drug use. The imperfect test gives positive results (indicating drug use) for 90% of all steroid-users but also (and incorrectly) for 2% of those who do not use steroids. Suppose that 5% of all registered athletes use steroids. If an athlete is tested negative, what is the probability that he/she uses steroids? SteroidsTask 1: A company has been running a television advertisement for one of its new products. A survey was conducted. Based on its results, it was concluded that an individual buys the product with probability 56%, if he/she saw the advertisement; and buys with probability 8%, if he/she did not see it. Twenty-five percent of people saw the advertisement. Plot a tree diagram with probability for the problem above. What is the probability that a randomly selected individual will buy the new product? c) What is the probability that at least one of randomly selected five individuals will buy the new product