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:
Step-by-step explanation:
Since there are nine 2s being multiplied by each other, we can represent this as .
Answer:
3.05 or 31/2 pounds
56 ounces
Step-by-step explanation:
To find the total weight all the weights have to have the same units of measurements
It is either pounds is converted to ounces or ounces is converted to pounds
1. convert ounces to pound
1 ounce = 0.0625
12 ounces = 0.0625 x 12 = 0.75 pounds or 3/4
add together = 1 1/2 + 3/4 + 1 1/4 = 
= 
= 3 1/2
2. 16 ounces = 1 pound
flour = 16 x 1 1/2 = 24
sugar = 16 x 1 1/4 = 20
total = 24 + 20 + 12 = 56 ounces
9) They traveled 31.9 hours over the 3-day trip.
10.9 + 8.6 + 12.4 = 31.9
10) She does not have enough money. She has $12, but everything she wants to purchase would cost $12.39.
Large drink = 1.79
Turkey sandwich = 4.85
1.79 + 4.85 = 6.64
6.64 + 5.75 = 12.39
What you do is you find the common denominator between the two fractions given. the easiest is to just multiply them
6*8=48
and then multiply each numerator by the number it's denominator is multiplied by
1*8=8 and 5*6=30
and now you have your new fractions, add them together
8/48+30/48=38/48
this leaves 10/48 as the people who were wearing shorts, just simplify this and it's done
10/2 =5/24
48/2
