2006 AP CSA FRQ 2: TaxableItem
Topic: Inheritance & Abstract Classes
Skills Tested: Abstract class extension, constructor chaining, method implementation, super keyword
Curriculum Alignment: Unit 3 (Class Creation) (2025-2026 AP CSA)
Points: 9 | Time Estimate: ~22 minutes
Study This Topic: Unit 3: Class Creation Complete Study Guide
Part (a)
Write the purchasePrice method in TaxableItem that calculates the total price including tax.
Try It First! Attempt to solve this part before viewing the solution.
Solution
public double purchasePrice()
{
double tax = getListPrice() * taxRate;
return getListPrice() + tax;
}Part (b)
Write the complete Vehicle class that extends TaxableItem with cost, markup, and the ability to change markup.
Solution
public class Vehicle extends TaxableItem
{
private double cost, markup;
public Vehicle(double cost, double markup, double taxRate)
{
super(taxRate);
this.cost = cost;
this.markup = markup;
}
public double getListPrice()
{
return cost + markup;
}
public void changeMarkup(double newMarkup)
{
markup = newMarkup;
}
}Key Concepts
✓ Abstract classes cannot be instantiated directly
✓ Subclasses must implement abstract methods (getListPrice)
✓ Use super(taxRate) to call parent constructor
✓ Instance variables should be private with appropriate methods
Common Mistakes to Avoid
✗ Forgetting to call super() in constructor
✗ Not implementing the abstract getListPrice method
✗ Accessing taxRate directly instead of through inherited behavior
✗ Missing instance variable declarations
Official College Board Resources
About the Author: Tanner Crow is a certified AP Computer Science teacher with 11+ years of experience.
Last updated: January 2026