Syracuse is the major hub for Travel Express International (Trax) for all its air cargo into and out of USA. Trax has its own airport in Syracuse and the airport operates 24/7. It has two independent runways; one handles the landings and the other handles the take-offs. The time interval between two consecutive landings is recorded throughout the day. Consider this time interval as random variable X. It is known that this random variable X follows exponential distribution with mean u standard deviation a (ie, mean equals standard deviation). Trax selects a simple random sample of 100 time-intervals each day, for all the 365 days of the year and calculated the average per day. If this sample average is less than 115 seconds, the team that handles the landings gets a bonus for that day. The team got the bonus 21.18 percent of the time. What is the expected value of the random variable X?

Select one:

O

a 135

b. 115

c. 130

d. 125

041