Answer:
at first we put the numbers in order from least to greatest
2 , 6 , 6 , 7 , 8 , 9
1st quartile = 6
median = (6+7)/2 = 6.5
3rd quartile = 8
The correct expressions are
-8.8
11(-2)
-6.7
Answer: 13,333 snowflakes
Step-by-step explanation:
For this exercise let be "x" represents the number of snowflakes that will be in the fort.
According to the information given in the exercise, the weight of one block is 1 kilogram. Knowing that the fort must have 40 blocks, the total weight is:

Since each snowflake weighs
grams, need to divide the total weight calculated above by the weight of a snowfake.
Therefore, through this procedure you get the following result:

Therefore, the there will be 13,333 snowflakes in the fort.
Answer:
Where
and 
We are interested on this probability

And the best way to solve this problem is using the normal standard distribution and the z score given by:

If we apply this formula to our probability we got this:
And we can find this probability using the complement rule:

Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where
and 
We are interested on this probability

And the best way to solve this problem is using the normal standard distribution and the z score given by:

If we apply this formula to our probability we got this:
And we can find this probability using the complement rule:

4/4=1. So we need to subtract 1 from 4 to get the final Answer which is 3.