Calling Instance Methods Practice Test

A Book class has methods: void checkOut(); void returnBook(); boolean isCheckedOut(). Book b = new Book("1984") starts checked out. How does calling b.returnBook() affect its state?

A Car class has methods: void service(String serviceType) records a service entry; int getMileage() returns mileage. Car car = new Car("Accord", 10000) exists. Which method call correctly records an oil change for car?