Let x be the cost of 1 pen
then cost of 1 notebook = x + 8.20
Let y be the number of pens Tan buys
then number of notebooks Tan buys = y/4
She spent $26 more on books than on pens which means
Cost of notebooks - Cost of pens = 26
(x + 8.20) * y/4 - xy = 26
Sinplifying it
(xy + 8.20y)/4 - xy = 26
(xy + 8.20y - 4xy)/4 = 26
8.20y - 3xy = 104
She spent $394 which means
Cost of notebooks + Cost of pens = 394
(x + 8.20) * y/4 + xy = 394
Simplifying it
(xy + 8.20y)/4 + xy = 394
(xy + 8.20y + 4xy)/4 = 394
8.20y + 5xy = 1576
Now, we have two equations,
(1) 8.20y - 3xy = 104
(2) 8.20y + 5xy = 1576
Now we need to find a third equation with either x or y as the subject of any of both the previous equations.
Let's make y the subject of (2) equation
8.20y + 5xy = 1576
y(8.20 + 5X) = 1576
(3) y = 1576/(8.20 + 5x)
Let's substitute the new value of y from (3) into (1) because we rearranged (2) to from (3)
8.20y - 3xy = 104
y(8.20 - 3x) = 104
y = 104/(8.20 - 3x)
1576/(8.20 + 5x) = 104/(8.20 - 3x)
1576 * (8.20 - 3x) = 104 * (8.20 + 5x)
12923.2 - 4728x = 852.8 + 520x
12923.2 - 852.8 = 4728x + 520x
12070.4 = 5248x
12070.4/5248 = x
x = 2.3
Now find the value of y by substituting the value of x in either equation, preferably (3)
y = 1576/(8.20 + 5x)
y = 1576/(8.20 + 5 * (2.3))
y = 80
Therefore cost of 1 notebook = x + 8.20 = 2.3 + 8.20 = $10.50
In the research, it should be noted that this is a Proportion, because worry or not worry is categorical
<h3>What is a proportion?</h3>
A population proportion is the percentage of the population that possesses a particular trait.
For illustration, suppose there are 1,000 people in the population and 237 of them have blue eyes. There are 237 blue eyed people out of every 1,000 people, or 237/1000.
Therefore, it should be noted that this is a Proportion, because worry or not worry is categorical.
Learn more about research on:
brainly.com/question/968894
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A poll shows that 64% of Americans personally worry a great deal about federal spending and the budget deficit. State whether the parameter of interest is a mean or a proportion.
So easy so easy so easy so easy so easy so easy so easy 9
Answer:
The third quartile is 56.45
Step-by-step explanation:
The given parameters are;
The first quartile, Q₁ = 30.8
The median or second quartile, Q₂ = 48.5
The mean, 
= 42.0
Coefficient of skewness = -0.38
The Bowley's coefficient of skewness (SK) is given as follows;
Plugging in the values, we have;
Which gives;
-0.38×(Q₃ - 30.8) = Q₃ + 30.8 - 2 × 48.5
11.704 - 0.38·Q₃ = Q₃ - 66.2
1.38·Q₃ = 11.704 + 66.2 = 77.904
Q₃ = 56.45
The third quartile = 56.45.
I thought this would be simple, as I'm familiar with algebra and not really "The constant of proportionality," but I will do my best.
So this said "Constant of proportionality," is referring to basically the answers for the equation when X equals certain numbers.
Make a table of different answers when you plug in X and you get the 'Constant of proportionality.'
y = 2.5x + 3
y = 2.5(1) + 3
y = 2.5 + 3
y = 5.5
Since we plugged in 1 for X and got 5.5 for Y, our input and output is (1, 5.5)
Replace X for a different value, and you will get a bunch of different numbers that will in essence be your function inputs and outputs. Make a table of these and you have your answer.
EXAMPLE -
-= x =- -= y =-
-= 1 =- -= 5.5 =-
-= 2 =- -= 8 =-
-= 3 =- -= 11.5 =-
-= 4 =- -= 13 =-
So there you have it. I hope this helps! If you have any further questions, don't hesitate to ask.
