Answer:
a) E(X)=1
b) σ=1
c) P(X>1)=0.368
d) P(2<X<5)=0.128
Step-by-step explanation:
We have X: "the time between two successive arrivals at the drive-up window of a local bank", exponentially distributed with λ = 1.
a) We have to compute the expected time between two successive arrivals.
The expected value for X as it is exponentially distributed is:

b) We have to compute the standard deviation of X.
The standard deviation is calculated as:

c) The probability that X is larger than 1 (P(X>1))
We can express the probability as:

d) The probability that X is between 2 and 5 (P(2<X<5))

Answer:
24
Step-by-step explanation:
Ratio of lambs to chickens is 3:1
So if chickens are 8 then lambs are 3 times more.
1u=8
3u=8×3
=24
Okay! In order to find 8 groups of .32 you'd simply divide them. So:
[.32 ÷ 8] = .04
To check you multiply:
[8 x .04] = .32.
The answer is .04