The answer is 12. Matthew would be 12 & Elizabeth would be 7. 12+7=19. So C is your answer.
Answer:
a=13m
Step-by-step explanation:
that's it in the picture
1. No answer ( may be due to incorrect question)
2. x = -3
y = 4
3. x= 4
y = 2
4.x = -63/40
y= -19/20
Step 1
Multiply equation 1 by the coefficient of x in equation 2
Multiply equation 2 by the coefficient of x I'm equation 1
(after completing this step you will derive equation 3 and 4 )
Step 2
Subtract equation 4 from equation 3
Step 3
Divide both sides of the equation by the coefficient of y
Step 4
substitute your value for y in equation 1 or 2
(after this you will derive the values of x)
Note : This method is for the Elimination of x
I hope it helps
Answer:
E[T] = 10
Step-by-step explanation:
A distribution is called uniform if each outcome has the same probability of happening.
The uniform distribution has two bounds, a and b, and the expected value of the uniform distribution is given by:

Uniformly distributed between 0 and 20 minutes.
This means that 
Let T be the number of minutes you wait until you board a bus. Find E[T].
This is
![E[T] = \frac{a + b}{2} = \frac{0 + 20}{2} = 10](https://tex.z-dn.net/?f=E%5BT%5D%20%3D%20%5Cfrac%7Ba%20%2B%20b%7D%7B2%7D%20%3D%20%5Cfrac%7B0%20%2B%2020%7D%7B2%7D%20%3D%2010)
E[T] = 10
There are a total of 297 students in the 7th grade. Rough estimates would say that about half of that number are boys and half are girls. Asking only 50 random girls would be biased because not only would it not be all of the girls (the number of girls would be around 148 or 149) but it would also be ignoring the roughly 148 to 149 boys there are on estimate. The sample would be biased because it would be ignoring the opinions of more than half the seventh grade.