The width of a rectangle is 7x-3.5 feet and the length is 3.5x + 10 feet. Find the perimeter of the rectangle

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.