<span>|5x - 1| < 1
-1 < 5x - 1 < 1
-1 + 1 < 5x < 1 + 1
0 < 5x < 2
0/5 < x < 2/5
0 < x < 2/5
</span>
Answer:

Step-by-step explanation:
Let h be the cylinders height and r the radius.
-The volume of a cylinder is calculated as:

-Since the cone is within the cylinder, it has the same radius as the cylinder.
-Let
be the height of the cone.
-The area of a cone is calculated as;

The volume of the solid section of the cylinder is calculated by subtracting the cone's volume from the cylinders:

Hence, the approximate area of the solid portion is 
You would solve this with simultaneous equations, so if we write it as:
5n + 2p = 9
3n + 2p = 6
(subtract)
2n = 3
÷ 2
notebooks = 1.5
Now you would substitute it in:
(3 × 1.5) + 2p = 6
4.5 + 2p = 6
- 4.5
2p = 1.5
÷ 2
pens = 0.75
So your final answer is notebooks are $1.50 and pens are $0.75, I hope this helps!
Answer:
--- Standard deviation
Step-by-step explanation:
Given
See attachment for graph
Solving (a): Explain how the standard deviation is calculated.
<u>Start by calculating the mean</u>
To do this, we divide the sum of the products of grade and number of students by the total number of students;
i.e.

So, we have:



Next, calculate the variance using the following formula:

i.e subtract the mean from each dataset; take the squares; add up the squares; then divide the sum by the number of dataset
So, we have:



Lastly, take the square root of the variance to get the standard deviation


--- approximated
<em>Hence, the standard deviation is approximately 11.28</em>
Considering the calculated mean (i.e. 82.76), the standard deviation (i.e. 11.28) is small and this means that the grade of the students are close to the average grade.