The table shows the total cost of purchasing the same priced items and a catalog.

[tex]\[
\begin{tabular}{|c|c|}
\hline
Number of Items & Total Cost \\
[tex]$( x )$[/tex] & [tex]$( y )$[/tex] \\
\hline
1 & \$10 \\
\hline
2 & \$14 \\
\hline
3 & \$18 \\
\hline
4 & \$22 \\
\hline
\end{tabular}
\][/tex]

What is the initial value and what does it represent?

A. \$4, the cost per item
B. \$4, the cost of the catalog
C. \$6, the cost per item
D. \$6, the cost of the catalog



Answer :

To find the initial value and understand what it represents, let us analyze the given data step by step.

We are given the table of the total cost \( y \) for purchasing \( x \) same-priced items along with the catalog:

[tex]\[ \begin{array}{|c|c|} \hline \text{Number of Items } (x) & \text{Total Cost } (y) \\ \hline 1 & \$10 \\ \hline 2 & \$14 \\ \hline 3 & \$18 \\ \hline 4 & \$22 \\ \hline \end{array} \][/tex]

### Step-by-Step Solution:

1. Identify the relationship:
The total cost \( y \) is a linear function of the number of items \( x \). We can represent it in the form:
[tex]\[ y = mx + b \][/tex]
where:
- \( m \) is the slope (cost per item),
- \( b \) is the y-intercept (initial value, representing the cost of the catalog).

2. Calculate the slope \( m \):
The slope \( m \) can be calculated using any two points from the table. For instance, using the points \((1, 10)\) and \((2, 14)\):
[tex]\[ m = \frac{y_2 - y_1}{x_2 - x_1} \][/tex]
Substituting the values:
[tex]\[ m = \frac{14 - 10}{2 - 1} = \frac{4}{1} = 4 \][/tex]
Thus, the cost per item is \( \boldsymbol{\$4} \).

3. Find the y-intercept \( b \):
Using one of the points and the value of \( m \), we can solve for \( b \). Let's use the point \((1, 10)\):
[tex]\[ y = mx + b \][/tex]
Substituting \( y = 10 \), \( x = 1 \), and \( m = 4 \):
[tex]\[ 10 = 4 \cdot 1 + b \\ 10 = 4 + b \\ b = 10 - 4 = 6 \][/tex]
Therefore, the initial value \( b \) is \( \boldsymbol{\$6} \).

### Interpretation:
- \$4 represents the cost per item.
- \$6 represents the cost of the catalog.

So, the correct answers are:
- \(\$4\), the cost per item
- [tex]\(\$6\)[/tex], the cost of the catalog

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