Wich letter is it? i don't understand

It takes evan 6 3/4 to mow 3 lawns. it takes 2 1/3 hours to mow me. gals lawn and 1 3/4 hot mow ms. lee’s lawn. how many hours does it take evan to mow the third lawn?

What is the value of the expression below? (81^2)^1/8

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.