A student's cost for last semester at her community college was $2700. She spent $486 of that on books. What percent of last semester's college costs was spent on books?

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.