- Determine the surcharge by substituting the known ride data into the linear equation \(y = 2.75x + b\), resulting in \(b = \$7.50\).
- Define the complete slope-intercept equation for the cab fare as \(y = 2.75x + 7.50\).
- Solve for the distance traveled by setting the total cost to \(\$35\) and calculating \(x\) in the equation \(35 = 2.75x + 7.50\).
- Conclude that the equation is \(y = 2.75x + 7.50\) and the distance traveled for \(\$35\) is \(\boxed{10 \text{ miles}}\).
Explanation
- Determining the Slope-Intercept Equation
To find the slope-intercept equation of the total cost of a cab ride, we use the linear form \(y = mx + b\), where \(y\) represents the total cost, \(x\) is the number of miles traveled, \(m\) is the cost per mile, and \(b\) is the fixed surcharge. We are given that the cost per mile \(m = \$2.75\) and that an 8-mile ride costs \(\$29.50\). We can substitute these values into the equation to determine the surcharge \(b\):
\[29.50 = 2.75(8) + b\]
Calculating the product:
\[2.75 \times 8 = 22.00\]
Subtracting this from the total cost gives:
\[b = 29.50 - 22.00 = 7.50\]
Thus, the fixed surcharge is \(\$7.50\), and the slope-intercept equation for the ride cost is:
\[y = 2.75x + 7.50\]
- Calculating the Distance for a Given Fare
Now that we have the equation \(y = 2.75x + 7.50\), we can determine the number of miles traveled for a total fare of \(\$35\). We set \(y = 35\) and solve for \(x\):
\[35 = 2.75x + 7.50\]
First, subtract the surcharge from both sides:
\[35 - 7.50 = 2.75x\]
\[27.50 = 2.75x\]
Divide both sides by the cost per mile \(2.75\):
\[x = \frac{27.50}{2.75} = 10\]
Therefore, a customer who paid \(\$35\) traveled 10 miles. The slope-intercept equation is \(y = 2.75x + 7.50\) and the distance for a \(\$35\) fare is \(10\) miles.
Examples
Understanding linear equations like \(y = mx + b\) is essential in everyday financial management. For example, when choosing between different mobile phone plans with a base monthly fee and an additional per-minute cost, or calculating the cost of a rental service, you are essentially solving for a total price based on usage. This problem demonstrates how to model such real-world costs mathematically, helping you make informed decisions about your expenses.