Andy works at a sporting goods store. Andy earns $400 every week plus $20 for every pair of shoes he sells. Andy wants to buy a motorcycle for $3200. Write an equation to represent this situation.

Monitors manufactured by tsi electronics have life spans that have a normal distribution with a standard deviation of 1800 hours and a mean life span of 20,000 hours. if a monitor is selected at random, find the probability that the life span of the monitor will be more than 17,659 hours. round your answer to four decimal places.