An airline has sold 560 tickets for a certain flight (with capacity 555 seats) in the assumption that not all passengers that purchased a ticket will arrive for the flight. Assume that the probability that a passenger will not show up for the flight is 1%, independently of all other passengers. How likely is it that there are more passengers showing up for the flight than seats are available? Calculate this probability by using a binomial distribution for the number of passengers that showed up for the flight.

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Answer:

There is a 34.09% probability that there are more passengers showing up for the flight than seats are available.

Step-by-step explanation:

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

[tex]P(X = x) = C_{n,x}.\pi^{x}.(1-\pi)^{n-x}[/tex]

In which [tex]C_{n,x}[/tex] is the number of different combinatios of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And [tex]\pi[/tex] is the probability of X happening.

For this problem,

There are 560 tickets, so [tex]n = 560[/tex]

There is a 1% probability that a passenger will not show up for the flight, so [tex]\pi = 0.01[/tex]

How likely is it that there are more passengers showing up for the flight than seats are available?

An airline has sold 560 tickets for a certain flight (with capacity 555 seats).

So, this question is: What is the probability that at most 4 passengers do not show up for the flight.

[tex]P = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4)[/tex]

[tex]P(X = x) = C_{n,x}.\pi^{x}.(1-\pi)^{n-x}[/tex]

[tex]P(X = 0) = C_{560,0}.(0.01)^{0}.(0.99)^{560} = 0.0036[/tex]

[tex]P(X = 1) = C_{560,1}.(0.01)^{1}.(0.99)^{559} = 0.0203[/tex]

[tex]P(X = 2) = C_{560,2}.(0.01)^{2}.(0.99)^{558} = 0.0574[/tex]

[tex]P(X = 3) = C_{560,3}.(0.01)^{3}.(0.99)^{557} = 0.1079[/tex]

[tex]P(X = 3) = C_{560,4}.(0.01)^{4}.(0.99)^{556} = 0.1517[/tex]

So

[tex]P = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) = 0.0036 + 0.0203 + 0.0574 + 0.1079 + 0.1517 = 0.3409[/tex]

There is a 34.09% probability that there are more passengers showing up for the flight than seats are available.