Hello!
Let's write some important information contained in the exercise:
• hotdogs: $2.59 (,x,)
,
• hamburgers: $5.29 (,y,)
He needs 11 packages. Let's write it:
• x + y = 11
He spent a total of $39.29. We can write it as:
• 2.59x + 5.29y = 39.29
Now, let's solve these two equations as a linear system:

First, let's isolate x in equation A:

Now, we will replace where's x by 11-y in equation B:

As I called the hamburgers as 'y', we know that he bought 4 packages of hamburgers.
A varible represents the number u are looking for.
Example:
2x + 3x
4- 2/3 (4-1/6) divided by 3/4
parenthesis first
4 - 2/3 (3 5/6) divided by 3/4
change to an improper fraction (6*3+5)/6
4 - 2/3 ( 23/6)divided by 3/4
4 - 46/18 divide by3/4
copy dot flip
4 - 46/18 * 4/3
4 - 23/9 * 4/3
4 - 92/27
get a common denominator of 27
4*27/27 -92/27
108/27 - 92/27
16/27
Answer:
(E) The bias will decrease and the variance will decrease.
Step-by-step explanation:
Given that researchers working the mean weight of a random sample of 800 carry-on bags to e the airline.
We have to find out the effect of increasing the sample size on variance and bias.
We know as per central limit theorem, sample mean follows a normal distribution with mean = sample mean
and std deviation of sample mean = std error = 
Thus std error the square root of variance is inversely proportional to the square root of sample size.
Also whenever we increase sample size the chances of bias would decrease as the sample size becomes larger
So correct answer is both bias and variation will decrease.
(E) The bias will decrease and the variance will decrease.
X = the dividend
x ÷ 7 = 13
x = 13x7
x = 91