my question

A professor of statistics noticed that the marks in his course are normally distributed. He also noticed that his morning classes average 70% with a standard deviation of 10% on their final exams. His afternoon classes average 78% with a standard deviation of 8%. A. What is the probability that a randomly selected student in the morning class has a higher final exam mark than a randomly selected student from an afternoon class? Probability = B. What is the probability that the mean mark of four randomly selected students from a morning class is greater than the average mark of four randomly selected students from an afternoon class? Probability =