Answer:
One number, let's call it x, is 6 more than twice the other number, let's say this number is y.
x= 2y+6
x+y=21
We're left with a system of equations.
If we substitute the first equation in the second we find the value of y.
(2y+6)+y=21
3y+6=21
3y=15
<u><em>y=5</em></u>
Now that we have found the value of y, we can take that value and substitute it in the second equation (since it's easier) to find the value of x.
x+ (5)=21
<u><em>x=16</em></u>
<u><em>Now to check if our answers are correct, we plug in both values into any equation and see if they equate.</em></u>
x+y=21
(16)+(5)=21
21=21
Our solution is correct!
Answer:

Step-by-step explanation:
5 = 6y
y = 
Answer:

And then the maximum occurs when
, and that is only satisfied if and only if:

Step-by-step explanation:
For this case we have a random sample
where
where
is fixed. And we want to show that the maximum likehood estimator for
.
The first step is obtain the probability distribution function for the random variable X. For this case each
have the following density function:

The likehood function is given by:

Assuming independence between the random sample, and replacing the density function we have this:

Taking the natural log on btoh sides we got:

Now if we take the derivate respect
we will see this:

And then the maximum occurs when
, and that is only satisfied if and only if:

Answer:
The probability they each indicate the same tire is 
Step-by-step explanation:
There will be 4 cases involved as there are 4 tires.
Probability of choosing front left tire is
as there are a total of 4 tires and we need to choose 1.
Now, if all the four students chose the front left tire then the probability is the product of individual probabilities.
Therefore, probability that all 4 students chooses front left tire is:

Similarly, the probabilities of choosing the remaining 3 tires by all the students would be:
,
, 
Therefore, the probability that they indicate the same tire is the sum of all these probabilities.
