Probability all 4 arrived w/in 15 min of sched. time, etc

[bgann]

Assume the likelihood that any flight of Northwest airlines arrives within 15 minutes of the scheduled tim is .90. We select four flights from yesterday for study.

a. What is the likelihood all four of the selectedflights arrived within 15 minutesof the scheduled time?

b. What is the likelihood that none of the selected flights arrived within 15 minutes of the scheduled time?

c. What is the likelihood at least one of the selected flights did not arrive within 15 minutes of the scheduled time?

Please help. I can't seem to understand the concept of stats.

 

[royhaas]

Read your textbook about independent events and the complement of an event.