Answer:
0.36427
Step-by-step explanation:
Mean = λ = 18 messages per hour
P(X = x) = (e^-λ)(λ⁻ˣ)/x!
P(X ≤ x) = Σ (e^-λ)(λ⁻ˣ)/x! (Summation From 0 to x)
But the probability required is that the messages thay come in an hour is between 15 and 20, that is, P(15 < X < 20)
P(15 < X < 20) = P(X < 20) - P(X ≤ 15)
These probabilities will be evaluated using a cumulative frequency calculator.
P(X < 20) = 0.65092
P(X ≤ 15) = poissoncdf(18, 15) = 0.28665
P(15 < X < 20) = P(X < 20) - P(X ≤ 15) = 0.65092 - 0.28665 = 0.36427.
You can use the Poisson distribution calculator here
https://stattrek.com/online-calculator/poisson.aspx
Answer:

Step-by-step explanation:
Answer:
B. the initial amount of money invested
Step-by-step explanation:
Principal is the money invested or the money that a lender lend the borrower. Such money is the basis on which the interest payable will be calculated after considering the numbers of years and installments.
Answer:
1. x = -37 - 7y
2. x = 7+3y/4
Answer:
a)
Surface Area: 172 cm^2
Volume: 112 cm^3
b) Surface Area
c) Volume
Step-by-step explanation: