Please help me answer showing working

4. A corporation must appoint a president, chief executive officer (CEO), chief financial officer (CFO) and chief operating officer (COO). It must also appoint a planning committee with four different members. These are 9 qualified candidates, and officers can also serve on the committee. (i) How many different ways can the officers be appointed? (1i) How many different ways can the committee be appointed? (iii) What is the probability of randomly selecting the committee members and getting the five youngest of the qualified candidates? 5. Given that P(A) = 0.7. P (A/B) = 0.7, P(AnB) = 0.42, find the following probabilities: a. P(B) b. P(B/A) C. P(A UB) d. P (AnB/ A UB) 6. The number of white corpuscles on a slide has a Poisson distribution with mean 4.5. a. Find the most likely number of white corpuscles om a slide. b. Calculate correct to three decima places the probability of obtaining this number c. If such two slides are prepared, what is the probability, correct to three decimals places of obtaining at least two white corpuscles in total on the two slides? 7. At Foodland Supermarket 45% of customers pay by credit card. Find the probability that in a randomly selected sample of fifteen customers. a. Exactly four pay by credit card b. More than ten pay by cash (give answers to 3 decimal places)