The average life expectancy of dishwashers produced by a company is 6 years with a standard deviation of 8 months. Assume that the lives of dishwashers are normally distributed. a, What is the probability that a randomly selected dishwasher will have a life expectancy of at least 7 years?

b, Dishwashers that fail to operate in less than 4.5 years will be replaced free of charge. What percent of dishwashers are expected to be replaced free of charge?

c, What are the minimum and maximum life expectancies of the middle 95% of dishwashers? Give your answer in months.

Please answer with the formula shown