The table represents a bicycle rental cost in dollars as a function of time in hours.

Bicycle Rental

[tex]\[
\begin{tabular}{|c|c|}
\hline
\text{Time (hours)} & \text{Cost (\$)} \\
\hline
0 & 0 \\
\hline
2 & 10 \\
\hline
4 & 20 \\
\hline
6 & 30 \\
\hline
8 & 40 \\
\hline
\end{tabular}
\][/tex]

Which explains whether or not the function represents a direct variation?

A. This function represents a direct variation because it passes through the origin and has a constant rate of change of \[tex]$5 per hour.

B. This function represents a direct variation because it has a positive, constant rate of change of \$[/tex]10 per hour.

C. This function does not represent a direct variation because it does not represent the cost for 1 hour.

D. This function does not represent a direct variation because the function rule for the cost is to add \$10, not multiply by a constant.



Answer :

To determine whether the function represents a direct variation, we need to check two conditions:
1. The function must pass through the origin (0,0).
2. The function must have a constant rate of change (slope).

Let's examine these conditions step by step:

### Step 1: Check if the Function Passes Through the Origin

From the table:
- At [tex]\( t = 0 \)[/tex] hours, the cost is \[tex]$0. Since the point (0,0) is included in the table, the function passes through the origin. ### Step 2: Check the Rate of Change Next, we need to determine the rate of change and see if it is consistent: - From \( t = 0 \) hours to \( t = 2 \) hours, the cost changes from \$[/tex]0 to \[tex]$10. \[ \text{Rate of change} = \frac{\$[/tex]10 - \[tex]$0}{2 - 0 \text{ hours}} = \frac{10}{2} = 5 \text{ dollars per hour} \] - From \( t = 2 \) hours to \( t = 4 \) hours, the cost changes from \$[/tex]10 to \[tex]$20. \[ \text{Rate of change} = \frac{\$[/tex]20 - \[tex]$10}{4 - 2 \text{ hours}} = \frac{10}{2} = 5 \text{ dollars per hour} \] - From \( t = 4 \) hours to \( t = 6 \) hours, the cost changes from \$[/tex]20 to \[tex]$30. \[ \text{Rate of change} = \frac{\$[/tex]30 - \[tex]$20}{6 - 4 \text{ hours}} = \frac{10}{2} = 5 \text{ dollars per hour} \] - From \( t = 6 \) hours to \( t = 8 \) hours, the cost changes from \$[/tex]30 to \[tex]$40. \[ \text{Rate of change} = \frac{\$[/tex]40 - \[tex]$30}{8 - 6 \text{ hours}} = \frac{10}{2} = 5 \text{ dollars per hour} \] The rate of change is constant at 5 dollars per hour. ### Conclusion Since the function passes through the origin and has a constant rate of change of 5 dollars per hour, we can conclude that the function represents a direct variation. The correct explanation is: This function represents a direct variation because it passes through the origin and has a constant rate of change of \$[/tex]5 per hour.