Normal Distribution Table website: https://www.ztable.net/

4. The counter checkout time presents a normal distribution, and the average and standard deviation are respectively It is between 8.3 minutes and 2.5 minutes, may I ask: (1) What is the probability that the checkout time is less than 3 minutes? (2) What is the probability that the checkout time is higher than 15 minutes? (3) What is the 10% checkout time for the fastest checkout?