am trying to solve following question and not sure I am doing it correct. I have provided answer to two questions here and my logic. Can someone please let me know if I am doing these right. The third question, I don't know how to do, any help will be much appreciated.
Assume the likelihood that any flight on an Airline arrives within 15 minutes of the scheduled time is 0.72. We select two flights from yesterday for study.
a. What is the likelihood all two of the selected flights arrived within 15 minutes of the scheduled time? Answer: Since probably of one flight within 15 minutes is 0.72, for two flights will be 0.72*0.72
b. What is the likelihood that none of the selected flights arrived within 15 minutes of the scheduled time? Answer: Probability for one flight arrival time not in 15 minutes is 1-0.72 = 0.28. Therefore for two flights it will be 0.28*0.28
c. What is the likelihood at least one of the selected flights did not arrive within 15 minutes of the scheduled time? Answer: I am not sure how to solve this