Answer:
abstract class Mark //Creating an Abstract class{
abstract double getPercentage();}
class A extends Mark{
double result;
A( int val1, int val2, int val3){
result=(val1+val2+val3)/3;}
double getPercentage(){
return result;}}
class B extends Mark{
double result;
B(int val1, int val2, int val3, int val4){
result=(val1+val2+val3+val4)/4;}
double getPercentage(){
return result;}}
class Main{
public static void main(String args[]){
//class A Object
Mark obj_1=new A(10,20,30);
System.out.println(obj_1.getPercentage());
//class B Object
Mark obj_2=new B(10,20,38,46);
System.out.println(obj_2.getPercentage());}}
