Answer: a) 0.9961, b) 0.9886
Step-by-step explanation:
Since we have given that
Probability that does not show up = 0.10
Probability that show up = 0.90
Here, we use "Binomial distribution":
n = 125 and p = 0.90
Number of passengers that hold in a flight = 120
a) What is the probability that every passenger who shows up can take the flight?
![P(X\leq 120)=\sum_{x=0}^{120}^{125}C_x(0.90)^x(0.10)^{125-x}=0.9961](https://tex.z-dn.net/?f=P%28X%5Cleq%20120%29%3D%5Csum_%7Bx%3D0%7D%5E%7B120%7D%5E%7B125%7DC_x%280.90%29%5Ex%280.10%29%5E%7B125-x%7D%3D0.9961)
(b) What is the probability that the flight departs with empty seats?
![P(X\leq 119)=\sum _{x=0}^{119}^{125}C_x(0.90)^x)(0.10)^{125-x}=0.9886](https://tex.z-dn.net/?f=P%28X%5Cleq%20119%29%3D%5Csum%20_%7Bx%3D0%7D%5E%7B119%7D%5E%7B125%7DC_x%280.90%29%5Ex%29%280.10%29%5E%7B125-x%7D%3D0.9886)
Hence, a) 0.9961, b) 0.9886