19. The table shows the total number of cars washed during a track team fundraiser. The slope of the line of best fit for the data is approximately 8. What does that 8 represent in terms of the context?

\begin{tabular}{|c|c|}
\hline Hour & \begin{tabular}{c}
Total Number of \\
Cars Washed
\end{tabular} \\
\hline 1 & 8 \\
\hline 2 & 17 \\
\hline 3 & 25 \\
\hline 4 & 30 \\
\hline 5 & 38 \\
\hline 6 & 50 \\
\hline
\end{tabular}

A. The track team washed 8 cars in the first hour.

B. The track team washes about 8 cars each hour.

C. Each hour, the track team washes about 8 more cars than they did in the previous hour.

D. The track team washes cars for 8 hours.



Answer :

To understand the meaning of the slope in this context, we should begin by recalling what a slope represents. The slope of a line measures the rate of change between the two variables being plotted; in this case, the "hours" and the "total number of cars washed."

Here are the steps to interpret the meaning of the slope:

1. Identify the Variables:
- The independent variable (x-axis) is the amount of time in hours.
- The dependent variable (y-axis) is the total number of cars washed.

2. Context of a Slope:
- The slope tells us how much the dependent variable (total number of cars washed) changes for each unit increase in the independent variable (hours).

3. Interpret the Given Slope:
- According to the problem, the slope of the line of best fit is 8.
- This means, on average, for every additional hour, the total number of cars washed increases by 8.

4. Analyze the Options:
- (A) The track team washed 8 cars in the first hour: This doesn't match the interpretation of a slope. It describes a specific number at a specific time, not a rate of change.
- (B) The track team washes about 8 cars each hour: This option aligns well with our understanding of the slope meaning that 8 cars are washed, on average, for each additional hour.
- (C) Each hour, the track team washes about 8 more cars than they did in the previous hour: This misinterprets the slope; the slope represents a consistent rate of change, not an increasing rate.
- (D) The track team washes cars for 8 hours: This doesn't relate to what a slope represents. It is about the duration, not the rate at which cars are washed.

5. Determine the Appropriate Answer:
- The slope of 8 means the rate at which the number of cars washed increases with time. Therefore, the best interpretation is that the track team washes about 8 cars for each hour.

The option that accurately reflects this interpretation is:

(B) The track team washes about 8 cars each hour.