Gina visited the aquarium with some of her cousins, aunts and uncles. The group bought 20 admissions tickets for $340. Adult tickets cost $20 and children’s tickets cost $15. How many adults and children’s tickets did the group buy?

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.