Airline passengers arrive randomly and independently at the passenger-screening facility
at a major international airport. The mean arrival rate is 10 passengers per minute.
a. Compute the probability of no arrivals in a one-minute period.
b. Compute the probability that three or fewer passengers arrive in a one-minute period.
c. Compute the probability of no arrivals in a 15-second period.
d. Compute the probability of at least one arrival in a 15-second period.

Respuesta :

Answer with Step-by-step explanation:

Since the random arrival process follows a poission's distribution

The probability of 'n' arrivals in time 't' is given by

[tex]P(n,t)=\frac{(\lambda t)^ne^{-\lambda t}}{n!}[/tex]

where

[tex]\lambda [/tex] is the average rate of arrival given as 10 passengers per minute

Part a)

[tex]P(0,1)=\frac{(10)^0\cdot e^{-10}}{0!}=0.0000454[/tex]

Part b)

The probability that 3 or lesser passengers arrive in 1 minute is the sum of the probabilities of arrival of no passenger , 1 passenger , 2 passengers or 3 passengers respectively

[tex]P(E)=\frac{(10)^0e^{-10}}{0!}+\frac{(10)^1e^{-10}}{1!} +\frac{(10)^2e^{-10}}{2!}+\frac{(10)^3e^{-10}}{3!}=0.01033[/tex]

Part c)

Since 15 seconds correspond to 0.25 minutes we have

[tex]P(0,0.25)=\frac{(10\times 0.25)^0\cdot e^{-10\times 0.25}}{0!}=0.082[/tex]

Part d)

Probability of at least one arrival in 15 seconds is

[tex]P=(1-p(0,0.25)\\\\P=1-0.082=0.918[/tex]