双精度值不能转换为布尔值

我只是不确定为什么会收到此错误，如果您能帮助我找出错误，我将不胜感激。这是代码，

import java.util.Scanner;

public class FirstSelectionProgram {

    public static void main(String[] args) {

        Scanner key=new Scanner(System.in);

        double spent;

        System.out.println("Please Enter The Amount That You Have Spent: ");
        spent= key.nextDouble();

        if (0.01=<spent && spent=<40)
        {
            System.out.println("you will receive 20% off");
        }
        else
        {
            System.out.println("you won't receive anything");
        }
    }
}