The final cost of a sale item is determined by multiplying the price on the tag by [tex]$75 \%$[/tex]. Which best describes the function that represents the situation?

\begin{tabular}{|c|c|}
\hline
Price on the Tag, [tex]$x$[/tex] & Final Cost \\
\hline
[tex]$\$[/tex]10[tex]$ & $[/tex]0.75(10)[tex]$ \\
\hline
$[/tex]\[tex]$20$[/tex] & [tex]$0.75(20)$[/tex] \\
\hline
[tex]$\$[/tex]30[tex]$ & $[/tex]0.75(30)[tex]$ \\
\hline
$[/tex]\[tex]$40$[/tex] & [tex]$0.75(40)$[/tex] \\
\hline
\end{tabular}

A. It is linear because the ratio of the change in the final cost compared to the rate of change in the price tag is constant.
B. It is linear because the function is continuous.
C. It is nonlinear because the final cost is determined by multiplying each price tag by 0.75.
D. It is nonlinear because the price tag and final cost columns do not have the same common difference.



Answer :

To determine which statement best describes the function that represents the situation where the final cost of a sale item is determined by multiplying the price on the tag by [tex]\(75\%\)[/tex], let's carefully analyze the provided tabular data and the relationship between the tag price and the final cost:

[tex]\[ \begin{tabular}{|c|c|} \hline Price on the Tag, $x$ & Final Cost $0.75x$ \\ \hline \$ 10 & $0.75(10) = \$7.50$ \\ \hline \$ 20 & $0.75(20) = \$15.00$ \\ \hline \$ 30 & $0.75(30) = \$22.50$ \\ \hline \$ 40 & $0.75(40) = \$30.00$ \\ \hline \end{tabular} \][/tex]

Next, we will determine if the relationship is linear by checking if the ratio of the final cost to the tag price is consistent across all given prices:

1. For a price tag of \[tex]$10, the final cost is \(0.75 \cdot 10 = \$[/tex]7.50\). The ratio is [tex]\(\frac{7.50}{10} = 0.75\)[/tex].
2. For a price tag of \[tex]$20, the final cost is \(0.75 \cdot 20 = \$[/tex]15.00\). The ratio is [tex]\(\frac{15.00}{20} = 0.75\)[/tex].
3. For a price tag of \[tex]$30, the final cost is \(0.75 \cdot 30 = \$[/tex]22.50\). The ratio is [tex]\(\frac{22.50}{30} = 0.75\)[/tex].
4. For a price tag of \[tex]$40, the final cost is \(0.75 \cdot 40 = \$[/tex]30.00\). The ratio is [tex]\(\frac{30.00}{40} = 0.75\)[/tex].

Since the ratio of the final cost to the tag price is constant at [tex]\(0.75\)[/tex] for all given prices, it indicates that the relationship between the tag price and the final cost is linear.

Thus, the correct statement is:

"It is linear because the ratio of the change in the final cost compared to the rate of change in the price tag is constant."