Step-by-step explanation:
a=2
b=-7
c=-15
-(-7)+-sq root (-7)²-4(2)(-15) / 2(2)
7 +- sq root 169 / 4
7+- 13 / 4
7+13 / 4, 7-13 / 4
x=5 x=-3/2
Answer:
hello,
Step-by-step explanation:
a)
p(fail)=0.05
p(not fail)=1-0.05=0.95
b)
p(3 fails)=0.05³=0,000125
c)
p(1 or more system not fail)=1-0.05³=0.999875
d)
it increase the security.( here 4/100 for 3 systems)
Answer:
Step-by-step explanation:
Let the number of hours Nick does the job alone to be x - 3 hours
Hence, in 1 hour, Nick has done 1/x - 3
Together they complete the job in 9 hours
Hence, let's represent the job as 1
9/x + 9/x - 3 = 1
Multiply through by (x)(x-3)
9(x- 3) + 9(x) = 1
9x - 27 + 9x = (x)(x-3)
-27 = x² - 3x
x² - 3x +27 = 0
The slope is the slope :D
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