# Question: the question i need assistance with is below probability of...

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The question I need assistance with is below:

Probability of a massive exposure of a toxic gas is obtained from a
Poisson distribution.

That is the rate of occurrence of the exposure, A, is constant in
time t, and the number of exposures

follows a Poisson distribution.

a.) What is the probability that no exposure occurs in time
t?

b.) If a regulation requires that the probability of a massive
exposure be less than 1-in-100 in a 30 years life of a plant

which produces this gas, what is the acceptable rate of occurrence
of this exposure?

I need help answering both parts (a) and (b).