Answer:
51/4
Step-by-step explanation:
To begin with you have to understand what is the distribution of the random variable. If X represents the point where the bus breaks down. That is correct.
X~ Uniform(0,100)
Then the probability mass function is given as follows.
Now, imagine that the D represents the distance from the break down point to the nearest station. Think about this, the first service station is 20 meters away from city A, and the second station is located 70 meters away from city A then the mid point between 20 and 70 is (70+20)/2 = 45 then we can represent D as follows
Now, as we said before X represents the random variable where the bus breaks down, then we form a new random variable 
, 
is a random variable as well, remember that there is a theorem that says that
![E[Y] = E[D(X)] = \int\limits_{-\infty}^{\infty} D(x) f(x) \,\, dx](https://tex.z-dn.net/?f=E%5BY%5D%20%3D%20E%5BD%28X%29%5D%20%3D%20%5Cint%5Climits_%7B-%5Cinfty%7D%5E%7B%5Cinfty%7D%20D%28x%29%20f%28x%29%20%5C%2C%5C%2C%20dx)
Where 
is the probability mass function of X. Using the information of our problem
![E[Y] = \int\limits_{-\infty}^{\infty} D(x)f(x) dx \\= \frac{1}{100} \bigg[ \int\limits_{0}^{20} x dx +\int\limits_{20}^{45} (x-20) dx +\int\limits_{45}^{70} (70-x) dx +\int\limits_{70}^{100} (x-70) dx \bigg]\\= \frac{51}{4} = 12.75](https://tex.z-dn.net/?f=E%5BY%5D%20%3D%20%5Cint%5Climits_%7B-%5Cinfty%7D%5E%7B%5Cinfty%7D%20%20D%28x%29f%28x%29%20dx%20%5C%5C%3D%20%5Cfrac%7B1%7D%7B100%7D%20%5Cbigg%5B%20%5Cint%5Climits_%7B0%7D%5E%7B20%7D%20x%20dx%20%2B%5Cint%5Climits_%7B20%7D%5E%7B45%7D%20%28x-20%29%20dx%20%2B%5Cint%5Climits_%7B45%7D%5E%7B70%7D%20%2870-x%29%20dx%20%2B%5Cint%5Climits_%7B70%7D%5E%7B100%7D%20%28x-70%29%20dx%20%20%5Cbigg%5D%5C%5C%3D%20%5Cfrac%7B51%7D%7B4%7D%20%3D%2012.75)
Answer:
y= -6
Step-by-step explanation:
-2y - 5y= -7y
-7y=42
42/-7=
y= -6
Answer:
28 gallons
Step-by-step explanation:
We are given that a sports car gets 14mpg in city driving and 19mpg for highway.
The model G=
Where G=Amount of gasoline used (in gal) for c miles driven in the city and h miles driven on the high way.
Amount of gas used in 14 miles car in the city driving=1 gal
Amount of gas used in 1 mile car in the city driving=
Amount of gas used in c miles car in the city driving =
gal
Similarly, for car driving on highway
Amount of gas used in h miles for car driving on highway=
c=98 miles in the city
h=399 miles on the highway
We have to find the amount of gas used required to derive 98 miles in the city and 399 miles on the highway.
Substitute the value of c and h in the given expression
Then, G=
Hence, the amount of gas required to derive 98 miles in the city and 399 miles on the highway=28 gallons
2 tens, 6 ones because the 2 is in the 10s place and the 6 is in the ones
Answer:
a students test score is likely to increase about 20 pointsfor each hour spent studying.
Step-by-step explanation:
i did the quiz and got it correct!!
