Sara Is a Frequent Business Traveler

Multiple Choice

Sara is a frequent business traveler. For security purposes, 10% of all people boarding airplanes are randomly selected for additional screening just prior to boarding. Define the random variable X = number of flights Sara completes before being chosen for additional screening. For instance, if she is searched boarding her next flight, then X = 0. What is the value of P(X = 2) = probability Sara completes two flights without screening and then is chosen for additional screening on the next one?

A) (0.1) ²
B) (0.9) ²
C) (0.1) ²(0.9)
D) (0.9) ²(0.1)