我想将总购买量显示为 11.10 而不是 11.1

I want to display the total purchase as 11.10 and not 11.1

输入图书价格:10 美元

图书成本:10.00 美元

征收州税:0.80 美元

征收县税:0.30 美元

总购买价格:11.10 美元

为什么我得到 11.1?

import java.util.Scanner;

public class Program1 {
    public static void main(String[] args) {
        Scanner kbd = new Scanner(System. in );

        double bookCost = kbd.nextDouble();
        double stateTax = bookCost * 0.08;
        double countyTax = bookCost * 0.03;
        double totalCost = bookCost + stateTax + countyTax;

        System.out.print("Enter the price of the book: $");

        System.out.println();
        System.out.println("Book Cost: $" + bookCost);
        System.out.println("State Tax Charged: $" + stateTax);
        System.out.println("County Tax Charge: $" + countyTax);
        System.out.println("Total Purchase Price: $" + totalCost);
    }
}

System.out.println( String.format( "%.2f", totalCost ) );