Answer:
Diego is 14 years old.
Sister is 19
Step-by-step explanation:
x = Diego's age
<u>x</u><u> </u><u>+</u><u> </u><u>2</u><u>4</u>
2x-9 = 2
First to get rid of the fraction we multiply each side by 2
2(2x-9) = 2((x+24)/2)
4x-18 = x+24
The we isolate x
4x-18 = x+24
<u>-x+18 -x+18</u>
<u>3x</u> = <u>42</u> Now we divide each side 3
3 3
x = 14
So Diego is 14
Now we can solve for his sister. We can use one of the two equations from earlier to do this.
Plug 14 in for x and then solve for his sister
2(14)-9
28-9
19
His sister is 19
Answer:
y=2
Step-by-step explanation:
Answer:
a) E(X) = 71
b) V(X) = 20.59
Sigma = 4.538
Step-by-step explanation:
<em>The question is incomplete:</em>
<em>According to a 2010 study conducted by the Toronto-based social media analytics firm Sysomos, 71% of all tweets get no reaction. That is, these are tweets that are not replied to or retweeted (Sysomos website, January 5, 2015).
</em>
<em>
Suppose we randomly select 100 tweets.
</em>
<em>a) What is the expected number of these tweets with no reaction?
</em>
<em>b) What are the variance and standard deviation for the number of these tweets with no reaction?</em>
This can be modeled with the binomial distribution, with sample size n=100 and p=0.71, as the probability of no reaction for each individual tweet.
The expected number of these tweets with no reaction can be calcualted as the mean of the binomial random variable with these parameters:

The variance for the number of these tweets with no reaction can be calculated as the variance of the binomial distribution:

Then, the standard deviation becomes:

Answer:
8 and 1 over 6 . Check it if you can , I wouldn't want you to get it wrong :)
Step-by-step explanation: