The amount of calories consumed by customers at the Chinese buffet is normally distributed with mean 2909 and standard deviation 580. One randomly selected customer is observed to see how many calories X that customer consumes. Round all answers to 4 decimal places where possible. The Piggy award will be given out to the 1% of customers who consume the most calories. What is the fewest number of calories a person must consume to receive the Piggy award? calories. (Round to the nearest calorie)

Can someone explain the breakdown of the equations used to find the answer - What is "z", what is "x", etc?