Every digits in 798 is greater than any digit in 4325 explain why 4325 is greater than 798

Evaluate 8j -k+148j−k+14 when j=0.25j=0.25 and k=1k=1.

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.

Me because i don't understand how to do it.: )