The ratio of the radio of sphere a and sphere b is ra\rb =2/5. the volume of sphere b is 64 pied cu ft. what is the volume of sphere a

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.