Answer:
<u>-5 ± √5² - 4 · 1 · 4</u>
2 · 1
Step-by-step explanation:
ax²+bx+c=0 (quadratic equation)
x=<u> -b ± √b² - 4ac</u>
2a
a= 1
b= 5
c= 4
-<u>5 ± √5² - 4 · 1 · 4</u>
2 · 1
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:
B and D
Step-by-step explanation:
To find the percentage, you divide Martin's correct answers by the total number of questions, then multiply the result by 100.
To find the fraction, it's <em>correct answers/total questions</em>.
E:very large numbers
hope this helps, pal
Answer:
the compound probability is 1/8.
Step-by-step explanation:
1/4 for the spinner x 1/2 for the coin