Finding a Constant of Proportionality

A scientist measured the water pressure at different depths. She made a table showing her findings. The [tex]$x$[/tex]-values represent the depth, in meters. The [tex]$y$[/tex]-values represent the pressure in atmospheres (atm).

\begin{tabular}{|c|c|}
\hline
[tex]$x$[/tex] & [tex]$y$[/tex] \\
\hline
0 & 0 \\
\hline
15 & 3 \\
\hline
30 & 6 \\
\hline
\end{tabular}

Assuming there is a proportional relationship, which additional set of values could be included in the table?

A. [tex]$(10, 2)$[/tex]

B. [tex]$(40, 9)$[/tex]

C. [tex]$(50, 38)$[/tex]

D. [tex]$(100, 76)$[/tex]



Answer :

Let's carefully analyze the data and determine which additional set of values could be included in the table, given that there's a proportional relationship between depth and pressure.

### Step-by-Step Solution

1. Understanding the Proportional Relationship:
- In a proportional relationship, the ratio [tex]\( \frac{y}{x} \)[/tex] (pressure to depth) is constant.

2. Given Data:
- Depth (x): 0, 15, 30 meters
- Pressure (y): 0, 3, 6 atmospheres

3. Finding the Constant of Proportionality (k):
- Choose any known pair of depth and pressure to calculate [tex]\( k \)[/tex].
- Using the pair (15, 3):
[tex]\[ k = \frac{y}{x} = \frac{3}{15} = 0.2 \][/tex]

4. Applying the Proportional Relationship:
- Using the constant [tex]\( k = 0.2 \)[/tex], we can write the relationship as:
[tex]\[ y = 0.2 \cdot x \][/tex]

5. Testing the Given Choices:
- Check which of the given choices fit the equation [tex]\( y = 0.2 \cdot x \)[/tex]:

- Choice (10, 2):
[tex]\[ y = 0.2 \cdot 10 = 2 \][/tex]
This fits because [tex]\( y = 2 \)[/tex].

- Choice (40, 9):
[tex]\[ y = 0.2 \cdot 40 = 8 \][/tex]
This does not fit because [tex]\( y \neq 9 \)[/tex].

- Choice (50, 38):
[tex]\[ y = 0.2 \cdot 50 = 10 \][/tex]
This does not fit because [tex]\( y \neq 38 \)[/tex].

- Choice (100, 76):
[tex]\[ y = 0.2 \cdot 100 = 20 \][/tex]
This does not fit because [tex]\( y \neq 76 \)[/tex].

6. Conclusion:
- The only set of values in the given choices that maintains the proportional relationship is [tex]\( (10, 2) \)[/tex].

Therefore, the set of values that could be included in the table while maintaining the proportional relationship is [tex]\( (10, 2) \)[/tex].