Answer:
a) Var[z] = 1600
D[z] = 40
b) Var[z] = 2304
D[z] = 48
c) Var[z] = 80
D[z] = 8.94
d) Var[z] = 80
D[z] = 8.94
e) Var[z] = 320
D[z] = 17.88
Step-by-step explanation:
In general
V([x+y] = V[x] + V[y] +2Cov[xy]
how in this problem Cov[XY] = 0, then
V[x+y] = V[x] + V[y]
Also we must use this properti of the variance
V[ax+b] =
V[x]
and remember that
standard desviation = ![\sqrt{Var[x]}](https://tex.z-dn.net/?f=%5Csqrt%7BVar%5Bx%5D%7D)
a) z = 35-10x
Var[z] =
Var[x] = 100*16 = 1600
D[z] =
= 40
b) z = 12x -5
Var[z] =
Var[x] = 144*16 = 2304
D[z] =
= 48
c) z = x + y
Var[z] = Var[x+y] = Var[x] + Var[y] = 16 + 64 = 80
D[z] =
= 8.94
d) z = x - y
Var[z] = Var[x-y] = Var[x] + Var[y] = 16 + 64 = 80
D[z] =
= 8.94
e) z = -2x + 2y
Var[z] = 4Var[x] + 4Var[y] = 4*16 + 4*64 = 320
D[z] =
= 17.88
Answer:

$124 higher
Step-by-step explanation:
Given


Required
Represent the situation
Determine how much higher or lower is the remaining amount
Let the initial amount in his account be represented with x
When he deposited, the balance becomes

When he withdrew, the balance becomes

Hence, the algebraic expression is

Calculating how much higher or lower

Open bracket


Recall that the initial amount in the account is x
The difference between the balance and the x is as follows


<em>Hence, the account has a higher of $124 after both transactions</em>
Answer:13.86km
Step-by-step explanation: see attachment
On your calculator your write 8 on the y axis and 4 on the x axis