Answer:
Mean = 1.42
Variance = 0.58
Step-by-step explanation:
Given: X denote the number of luxury cars sold in a given day, and Y denote the number of extended warranties sold.
Also, joint probability function of X and Y are given.
To find:
mean and variance of X
Solution:
From the given joint probability function of X and Y,
Mean of X:
Variance of X:
![var(X)=E\left [ X^2 \right ]-\left ( E\left [ X \right ] \right )^2\\=\frac{31}{12}-\left ( \frac{17}{12} \right )^2\\=\frac{31}{12}-\frac{289}{144}\\=\frac{372-289}{144}\\=\frac{83}{144}\\=0.58](https://tex.z-dn.net/?f=var%28X%29%3DE%5Cleft%20%5B%20X%5E2%20%5Cright%20%5D-%5Cleft%20%28%20E%5Cleft%20%5B%20X%20%5Cright%20%5D%20%5Cright%20%29%5E2%5C%5C%3D%5Cfrac%7B31%7D%7B12%7D-%5Cleft%20%28%20%5Cfrac%7B17%7D%7B12%7D%20%5Cright%20%29%5E2%5C%5C%3D%5Cfrac%7B31%7D%7B12%7D-%5Cfrac%7B289%7D%7B144%7D%5C%5C%3D%5Cfrac%7B372-289%7D%7B144%7D%5C%5C%3D%5Cfrac%7B83%7D%7B144%7D%5C%5C%3D0.58)
Answer:
the answer is a where x=8
Explanation:
cross multiplication method
The equation is:
h ( t ) = - 16 t² + 60 t + 3
The toy rocket will reach the ground when: h ( t ) = 0
- 16 t² + 60 t + 3 = 0
t 1 = - 0.05
t 2 = 3.8
Answer:
C ) 3.80 s
Answer: a slice of pizza cost $1.25 and a 12-ounce cola cost $0.50.
Step-by-step explanation:
Let slice of pizza cost x and a 12-ounce cola cost y.
Then Sara's order cost: 2x+y=3
and Sydney's order cost: 3x+2y=4.75
From the first equation we have: y=3-2x and put this to the second equation:
3x+2(3-2x)=4.75
3x+6-4x=4.75
x=1.25
y=3-1.25*2=0.50
Answer: a slice of pizza cost $1.25 and a 12-ounce cola cost $0.50.
