Look at picture there is question

Nick estimated that 5/8+4/7 is about 2.explain how you know his estimate is not reasonable plz and fast i will give 50 points

Select the two pairs of figures that are similar.

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.