Answer:
Step-by-step explanation:
Let GS denote the good service and SP denote the signal problem.
A subway has good service 70% of the time, that is, and a subway runs less frequently 30% of the time because of the signal problems, that is, .
If there are signal problems, the amount of time T in minutes that have to wait at the platform is described by the probability density function given below:
If there is good service, the amount of time T in minutes that have to wait at the platform is described the probability density function given below:
(a)
The probability that you wait at least 1 minute if there is good service P(T ≥ 1| GS) is obtained as follows:
(b)
The probability that you wait at least 1 minute if there is signal problems P(T ≥ 1| SP) is obtained as follows:
(c)
After 1 minute of waiting on the platform, the train is having signal problems follows an
exponential distribution with parameter
The probability that the train is having signal problems based on the fact that will be at least 1 minute long is obtained using the result given below:
Now calculate the as follows:
The probability that the train is having signal problems based on the fact that will be at least 1 minute long is calculated as follows:
Hence, the probability that the train is having signal problems based on the fact that will be at least 1 minute long is .
(d)
After 5 minutes of waiting on the platform, the train is having signal problems follows an exponential distribution with parameter .
The probability that the train is having signal problems based on the fact that will be at least 5 minutes long is obtained using the result given below:
First, calculate the as follows:
Now, calculate the as follows:
Now, calculate the as follows:
The probability that the train is having signal problems based on the fact that will be at least 5 minutes long is calculated as follows:
Hence, the probability that the train is having signal problems based on the fact that will be at least 1 minute long is .