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:16y I think
Step-by-step explanation:
Take out the y, 2+5-3 is 4, and to the second power is multiplying 4 twice, so 16. theyre all have the same variable to the right, so 16y
12s + 5 = 77
12s = 77 - 5 = 72
s = 72/12
s = 6 ...//
Ans = C ... 12x + 5 = 77 ...
In this case, you aren't going to get an integer for the value of a, but you can rearrange the equation to equal a.
4a-3=D add 3 to both sides
4a=D+3 divide both sides by 4
a=(D+3)/4 here's your answer