h = prob of hardcover = .25
p = prob of paperback = .75
a.
Prob(2 hardcover of 10) = (10 choose 2) (.25)^2 (.75)^8
= ( 10(9)/2 ) (1/4^10) (1^2 3^8)
= 295245/1048576
≈ 28.15%
b.
I think I just did the binomial distribution. We can approximate it as a normal distribution. The mean and variance in this case are computed thus:
N=10, n=2
μ = Np = 2.5
σ² = Npq = 1.875
σ = 1.3693
P(n) = 1/(σ√2π)e^-(n-μ)/(2σ²)
P(2) = 1/(1.3693√2π)e^-(2 - 2.5)/(2 (1.875))
P(2) = 33.3%
Pretty good, not great.
Answer: 2 numbers are 19 and 39
Step-by-step explanation:
<em>y = x + 20</em>
Equation: x + y + 20 = 78
⇔ x + y = 78 - 20
⇔ x + y = 58
⇔ y = 58 - x
So, we have:
x + 20 = 58 - x ( = y)
⇔ x + x = 58 - 20
⇔ 2x = 38
⇔ x = 19
⇒ y = x + 20 = 19 + 20 = 39
Answer:
h=20
Step-by-step explanation:
h=3 (V/lw)
h= 3 (960/12*12)
Answer:
9 days
Step-by-step explanation:
He sets his watch 12 seconds behind
For every day that passes it falls back another 1 second
So once it is 21 seconds behind all you have to do is subtraction to find the amount of days past
21 - 12 = 9
Since its 12 seconds behind already itll take 9 days to be behind 9 more seconds.
A.40,48 is the right answer
