Main2.java

abstract class Marks{

    abstract double getPercentage();
}
class A extends Marks{

        int sub1,sub2,sub3;
        int sum;
        double per;

        A(int sub1,int sub2,int sub3) {
            this.sub1 = sub1;
            this.sub2 = sub2;
            this.sub3 = sub3;
        }
        double getPercentage(){

            sum=sum+sub1+sub2+sub3;
            per = (sum*100)/300;
            return per;
    }

}
class B extends Marks{

    int sub1,sub2,sub3;
    int sum=0;
    double per;

    B(int sub1,int sub2,int sub3) {
        this.sub1 = sub1;
        this.sub2 = sub2;
        this.sub3 = sub3;
    }
    double getPercentage(){

        sum=sum+sub1+sub2+sub3;

        return sum;
    }

}
public class Main2 {
    public static void main(String[] args) {

        A obj = new A(50,50,50);
        double ans1 = obj.getPercentage();
        System.out.println(ans1);

    }
}