A manufacturer knows that their items have a normally distributed length, with a mean of 15.4 inches, and standard deviation of 2.7 inches. If one item is chosen at random, what is the probability that it is less than 11.5 inches long

The weekly amount spent by a company for travel has an approximately normal distribution with mean = $550 and standard deviation = $40. a) what is the probability that the actual weekly expense will exceed $570 for more than 20 weeks during the next year? (note: one year = 52 weeks) b) what is the probability that actual weekly expenses exceed $580 for 10 or more, but 16 or fewer weeks during the next year?