这个题怎么做，求回答

public class Booth {
    
    public static void main(String[] args) {
        
        Booth booth = new Booth();
        System.out.println(String.format("求两数之和：%d", booth.sum(10, 12)));
        System.out.println(String.format("求三数之平均值：%d", booth.average(12, 13, 2)));
    }
    
    public int sum(int a, int b) {
        return a + b;
    }
    
    public int average(int a, int b, int c) {
        return (a + b + c) / 3;
    }
}

有用望采纳

package day01;

public class Sum {
private int sum(int a, int b){
int resultSum;
resultSum = a+b;
return resultSum;
}
private int average(int a,int b,int c){
int sum,resultAverage;
int parameter = 3;
sum = a+b+c;
resultAverage = sum/parameter;
return resultAverage;
}

public static void main(String[] args) {
    Sum res = new Sum();
    System.out.println( res.sum(10,2));
    System.out.println(res.average(2,20,2) );
}

}