A travelling salesman sells milkshake mixing machines and on average sells 8.9 machines per month. He needs to sell at least 3 machines each month order to stay in business, otherwise he will shut down. Using the Poisson distribution, what is the probability he will have to shut down after this month

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Answer:

0.67% probability he will have to shut down after this month

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 time interval.

On average sells 8.9 machines per month.

So [tex]\mu = 8.9[/tex]

Using the Poisson distribution, what is the probability he will have to shut down after this month

If he sells less than 3 machines.

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

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

[tex]P(X = 0) = \frac{e^{-8.9}*8.9^{0}}{(0)!} = 0.0001[/tex]

[tex]P(X = 1) = \frac{e^{-8.9}*8.9^{1}}{(1)!} = 0.0012[/tex]

[tex]P(X = 2) = \frac{e^{-8.9}*8.9^{2}}{(2)!} = 0.0054[/tex]

[tex]P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0001 + 0.0012 + 0.0054 = 0.0067[/tex]

0.67% probability he will have to shut down after this month