1) the lenght of life of the whirlpool washer s approximately normally distributed wiht the mean of 3.1 years and standard deviation of 1.2 years . If this thyp of washer is guaranteed for one year , what fraction of original sales will require replacement?
2) the time it takes to come to school is approximately normally distributed with a mena of 45 minutes and standard deviation of 3 minutes . what time must yo leave home in the moring so that you are 95% sure of arriving by 9 am