C :

#include<stdio.h>
int main()
{
	int n;
	scanf("%d",&n);
	int i,j,a[n][3];
	for(i=0;i<n;i++){
		for(j=0;j<3;j++){
			scanf("%d",&a[i][j]);
		}
	}
	
	for(j=0;j<3;j++){
		double t;
		int s=0;
		for(i=0;i<n;i++){
			s+=a[i][j];
			t=(double)s/n;
		
		} 
		printf("%.1f ",t);
			 
	} 
	return 0;
}

C++ :

#include <bits/stdc++.h>
using namespace std;

int main(){
	int a[100][3];
	int n,i,j,s;
	double v;
	cin>>n;
	for(i = 0;i < n;i++){
		for(j = 0;j < 3;j++){
			cin>>a[i][j];
		} 
	}
	
	//先循环科目 
	for(j = 0;j < 3;j++){
		s = 0;
		//再循环人 
		for(i = 0;i < n;i++){
			//cout<<a[i][j]<<" ";
			s = s + a[i][j];
		} 
		
		v = s * 1.0 / n;//n个科目的成绩 
		cout<<fixed<<setprecision(1)<<v<<" ";
	}
}

Python :

n = int(input())
a = [[0 for j in range(3)] for i in range(n)]

yw = 0
sx = 0
yy = 0
for i in range(n):
    t = input().split()
    for j in range(3):
        a[i][j] = int(t[j])

for i in range(n):
    yw += a[i][0]
    sx += a[i][1]
    yy += a[i][2]
print('%.1f %.1f %.1f' % (yw / n, sx / n, yy / n), end='')