Let
denote the value on the
-th drawn ball. We want to find the expectation of
, which by linearity of expectation is
![E[S]=E\left[\displaystyle\sum_{i=1}^5B_i\right]=\sum_{i=1}^5E[B_i]](https://tex.z-dn.net/?f=E%5BS%5D%3DE%5Cleft%5B%5Cdisplaystyle%5Csum_%7Bi%3D1%7D%5E5B_i%5Cright%5D%3D%5Csum_%7Bi%3D1%7D%5E5E%5BB_i%5D)
(which is true regardless of whether the
are independent!)
At any point, the value on any drawn ball is uniformly distributed between the integers from 1 to 10, so that each value has a 1/10 probability of getting drawn, i.e.

and so
![E[X_i]=\displaystyle\sum_{i=1}^{10}x\,P(X_i=x)=\frac1{10}\frac{10(10+1)}2=5.5](https://tex.z-dn.net/?f=E%5BX_i%5D%3D%5Cdisplaystyle%5Csum_%7Bi%3D1%7D%5E%7B10%7Dx%5C%2CP%28X_i%3Dx%29%3D%5Cfrac1%7B10%7D%5Cfrac%7B10%2810%2B1%29%7D2%3D5.5)
Then the expected value of the total is
![E[S]=5(5.5)=\boxed{27.5}](https://tex.z-dn.net/?f=E%5BS%5D%3D5%285.5%29%3D%5Cboxed%7B27.5%7D)
Answer:
2. B
3. C
4. B
5. D
Step-by-step explanation:
2) The sequence is multiplying by -2 each time. This means that it is geometric.
The next two terms would be:

This means that the answer is B
3) The sequence is being multiplied by
each time. This means that it is geometric.
The next 3 terms would be:

I am assuming that the answer is C and that you were unable to type the fractions.
4) We know that the common difference is 1.5, so that is the coefficient of our variable and the starting value is 15. This means that we can write an equation as follows

Now we can find the first 4 terms

This would mean that the answer is B
5) We know that this is a geometric series, we know the common ratio, and we know the first term. This means we can write the equation as follows

Now we can find the first 4 terms

Unless you meant that the ratio was
, the answer is D, none of the above
Answer:
5/8
Step-by-step explanation:
The probability of not getting blue can be found by dividing the number of sections that are not blue by the total number of sections.
P(not blue)= not blue / total
There are a total of 8 sections. 3 are blue, which leaves 5 that are not blue (1 yellow, 2 red and 2 green).
not blue= 5
total= 8
P ( not blue)= 5/8
This fraction cannot be reduced, therefore our answer is 5/8
Answer:
106 boys
Step-by-step explanation:
7th grade = 159 students
Boys to girls ratio:
2:1
Find two thirds of 159:
2/3*159 = 106 boys
159-106= 53 girls
Check:
53*2 = 106