You grow plants for a science project. one plant is 11 3/4 inches tall. another plant is 7 5/8 inches tall. find the difference in the heights of the plants.

The ages of personnel in the accounting department of a large company are normally distributed with a standard deviation of 7 years. there is a 0.02275 probability that the age of any randomly chosen person in the department is less than 22 and 0.15866 probabilty that the age of any randomly chosen person is greater than 43. what is the mean of this distribution?