Tracy spends $97 on her cell phone bill this month. Her bill is usually around the same amount each month. If she wants to include an estimate of her cell phone bill in her monthly budget, what amount should she use? Round to the nearest ten? A.$90
B.$97
C.$100
D.$200

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.