Select the correct answer.

\begin{tabular}{|c|c|}
\hline[tex]$x$[/tex] & [tex]$y$[/tex] \\
\hline 2.5 & 0.400 \\
\hline 9.4 & 0.106 \\
\hline 15.6 & 0.064 \\
\hline 19.5 & 0.051 \\
\hline 25.8 & 0.038 \\
\hline
\end{tabular}

The table lists the values for two parameters, [tex]$x$[/tex] and [tex]$y$[/tex], of an experiment. What is the estimated value of [tex]$x$[/tex] for [tex]$y=0.049$[/tex]?

A. 20.4
B. 21.4
C. 23.7
D. 24.7



Answer :

To estimate the value of [tex]\(x\)[/tex] for [tex]\(y = 0.049\)[/tex], we first need to identify the interval in the given table where the [tex]\(y\)[/tex] value falls between the values provided.

Looking at the table:
[tex]\[ \begin{array}{|c|c|} \hline x & y \\ \hline 2.5 & 0.400 \\ \hline 9.4 & 0.106 \\ \hline 15.6 & 0.064 \\ \hline 19.5 & 0.051 \\ \hline 25.8 & 0.038 \\ \hline \end{array} \][/tex]

We see that [tex]\(0.049\)[/tex] lies between [tex]\(0.051\)[/tex] (at [tex]\(x = 19.5\)[/tex]) and [tex]\(0.038\)[/tex] (at [tex]\(x = 25.8\)[/tex]).

Next, we use linear interpolation to estimate the value of [tex]\(x\)[/tex] for [tex]\(y = 0.049\)[/tex].

The linear interpolation formula is:
[tex]\[ x = x_1 + \frac{(x_2 - x_1) \cdot (y - y_1)}{(y_2 - y_1)} \][/tex]

For our specific case:
- [tex]\(x_1 = 19.5\)[/tex]
- [tex]\(x_2 = 25.8\)[/tex]
- [tex]\(y_1 = 0.051\)[/tex]
- [tex]\(y_2 = 0.038\)[/tex]
- [tex]\(y = 0.049\)[/tex]

Plugging in the values, we get:
[tex]\[ x = 19.5 + \frac{(25.8 - 19.5) \cdot (0.049 - 0.051)}{(0.038 - 0.051)} \][/tex]

Simplifying the expression inside the fraction:
[tex]\[ x = 19.5 + \frac{6.3 \cdot (-0.002)}{-0.013} \][/tex]

[tex]\[ x = 19.5 + \frac{-0.0126}{-0.013} \][/tex]

[tex]\[ x = 19.5 + 0.9692307692307692 \][/tex]

[tex]\[ x \approx 20.469230769230766 \][/tex]

Rounding this to the nearest tenth, we get:
[tex]\[ x \approx 20.4 \][/tex]

Therefore, the correct answer is:
A. 20.4