The number of days, d, required to complete a job varies inversely as the number of workers, w, on the job. If it takes 9 days for 8 workers to complete a job, then how many workers would it take to do the job in 18 days?

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.