5. Suppose the probability of purchasing a defective computer is 0.02. What is the probability of (a) purchasing 2 defective computers in a group of 10? (3 marks) (b) purchasing at least 2 defective computers in a group of 15? (3 marks) 6. The mean rate of cars enter the parking is 20 cars in one hour. Find the probability of exactly 15 cars entering the parking in half hour duration. (4 marks) 4b5d68111cc340353d34b7a8b11a5 eb 7. For a certain type of computers, the length of time between charges of the battery is normally distributed with a mean of 41 hours and a standard deviation of 17 hours. John owns one of these computers and wants to know the probability that the length of time will (a) less than 75 hours. (b) between 40 and 70 hours. (3 marks) (2 marks)