Answer:
-5r + 8r +5
= (-5+8)r+5 (we can calculate number in same variabe)
= 3r +5
hope it helps ^°^
Answer:
(a)
(b)
Step-by-step explanation:
Let X and Y be discrete random variables and E(X) and Var(X) are the Expected Values and Variance of X respectively.
(a)We want to show that E[X + Y ] = E[X] + E[Y ].
When we have two random variables instead of one, we consider their joint distribution function.
For a function f(X,Y) of discrete variables X and Y, we can define
Since f(X,Y)=X+Y
Let us look at the first of these sums.
Similarly,
Combining these two gives the formula:
Therefore:
(b)We want to show that if X and Y are independent random variables, then:
By definition of Variance, we have that:
Since X and Y are independent, Cov(X,Y)=0
Therefore as required:
The answer is i thinks x=3
Assuming that all the grapes have the same probability of being randomly picked:
<h3>
How to find the probabilities?</h3>
We know that there are 8 green grapes and 15 red grapes on the bowl, so there is a total of 23 grapes.
a) Here we need to find the probability that both grapes are green. Remember that the probability of getting a green grape is equal to the quotient between the number of green grapes and the total number of grapes, this is:
P = 8/23
But then he must take another, because he already took one, the number of green grapes is 7, and the total number of grapes is 22, so for the second grape the probability is:
P' = 7/22.
The joint probability is the product of the two individual probabilities:
prob = (8/23)*(7/22) = 0.11
b) For the first green grape we know that the probability is:
P = 8/23
Then he must get a red grape. There are 15 red grapes and 22 grapes in total, so the probability is:
P' = 15/22
Then the joint probability is:
prob = (8/23)*(15/22) = 0.24
If you want to learn more about probability:
brainly.com/question/25870256
#SPJ1
Answer:
For 90 minutes of TV there will be 24 mins of commercials
Step-by-step explanation:
You start with 30 and keep adding 30 mins each time until you get to 90. (So..30..60..90) each time you add 30mins you add 8 more minutes to the commercials)
30 mins tv----8mins commercials
60 mins tv----16mins commercials
90 mins tv----24mins commercials
Hope this helps, good luck!