Answer:
0.77978
Explanation:
This is a Poisson distribution problem
Poisson distribution formula is given as
P(X = x) = (e^-λ)(λˣ)/x!
λ = mean = 10 tankers per day
x = variable whose probability is required
The probability that more than 7 tankers arrives in a certain day = 1 - (Probability that 7 or less tankers arrive in a certain day)
P(X > 7) = 1 - P(X ≤ 7)
P(X ≤ x) = Σ (e^-λ)(λˣ)/x! (Summation From 0 to x)
P(X ≤ 7) = P(X=0) + P(X=1) + P(X=2) + P(X=3) + P(X=4) + P(X=5) + + P(X=6) + P(X=7) + P(X=8)
Computing this,
P(X≤7) = 0.22022
P(X > 7 ) = 1 - P(X≤7) = 1 - 0.22022 = 0.77978
