Please help me with an explanation so i can understand it better

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.

Joe bought 4.25 pounds of pears for $7.18. if the equation 4.25x = 7.18models the situation, what does the variable stand for?

Michele wanted to measure the height of her school’s flagpole. she placed a mirror on the ground 48 feet from a flagpole, then walked backwards until she was able to see the top of the pole in the mirror. her eyes were 5 feet above the ground and she was 12 feet from the mirror. using similar triangles, find the height of the flagpole to the nearest hundredth of a foot.