If each garden takes 20 minutes to clean, it will take him (20 x 4) to clean the gardens.
20 x 4 = 100
80 minutes
or 1 hour and 10 minutes.
First solve the triangle:
75° + 75° + x = 180°
150° + x = 180°
x = 180° - 150°
Therefore x = 30°
Then, use the geometrical property of vertically opposite angles.
Therefore. x° = 30°
Answer:
5x maybe dont take my word
Using the binomial distribution, it is found that the mean and the standard deviation of variable x are given as follows:

<h3>What is the binomial probability distribution?</h3>
It is the probability of exactly <u>x successes on n repeated trials, with p probability</u> of a success on each trial.
The expected value of the binomial distribution is:
E(X) = np
The standard deviation of the binomial distribution is:

In this problem, we have that the parameters are given as follows:
n = 4, p = 0.75.
Hence the mean and the standard deviation are given as follows:
- E(X) = np = 4 x 0.75 = 3.
More can be learned about the binomial distribution at brainly.com/question/24863377
#SPJ1
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