At a certain university, the mean age of cars driven to school by students had a mean of 7.85 years with a standard deviation of 3.04 years. Assuming a normal distribution for car age,: (a)What fraction of students drove cars at least ten years old to school? (b)In a random sample of 50 students, what is the probability that the sample mean age of cars driven by students falls between 7.50 and 8.00 years