Grace's average in math for the first nine weeks was an 88. her second nine weeks average decreased 12.5%. what was her average for the second nine weeks?

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.