Seeking step by step and how to use excel for these functions.

Question 3: The grade of statistics final exam is normally distributed, suppose the population mean equals to 73 and standard deviation equals to 18. Use the information to answer question 2 below.

What is the probability that a randomly selected student that has grade less than 60? Please show the steps on how you calculate the Z-score, please show me the Excel formula/syntax , then the probability calculated

2. What is the probability that a randomly selected student that has grade greater than 90? Please show the steps on how you calculate the Z-score, and the Excel formula/syntax , and the probability

3. What is the probability that FOUR randomly selected students (hint: sample mean) that have grades between 70 and 79? Please show the steps on how you calculate the Z-score, the Excel formula/syntax , then the probability.