Alexander is a salesperson who sells computers at an electronics store. He makes a base pay of $90 each day and then is paid a $2.50 commission for every computer sale he makes. Write an equation for P, in terms of x, representing Alexander's total pay on a day on which he sells a computers.
P =

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.