(10 points) It is known that cars arrive at a drive-through at a rate of three cars per minute between 12 noon and 1:00 pm. Assuming the number of cars that arrive in any time interval follows a Poisson distribution, what is the probability that exactly 9 cars arrive between 12:10 and 12:20. (Note: the question gives the rate is

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Answer:

0.000005 probability that exactly 9 cars arrive between 12:10 and 12:20.

Step-by-step explanation:

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]

In which

x is the number of sucesses

e = 2.71828 is the Euler number

[tex]\mu[/tex] is the mean in the given interval.

Mean of 3 cars per minute:

So, between 12:10 and 12:20, there is an interval of 10 minutes, which means that [tex]\mu = 3*10 = 30[/tex]

What is the probability that exactly 9 cars arrive between 12:10 and 12:20?

This is [tex]P(X = 9)[/tex]. So

[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]

[tex]P(X = 9) = \frac{e^{-30}*30^{9}}{(9)!} = 0.000005[/tex]

0.000005 probability that exactly 9 cars arrive between 12:10 and 12:20.