C :

#include<stdio.h>
int main()
{
	int a,b,c;
	scanf("%d",&a);
	printf("%d\n%d\n%.1f",a*3,a*3-8,(a*7-8)*1.0/3);
	return 0;
}

C++ :

#include<iostream>
#include <iomanip>
using namespace std;
int main(){
	int x;
	cin>>x;
	cout<<x*3<<endl;
	cout<<x*3-8<<endl;
	cout<<fixed<<setprecision(1)<<(x*3+x*3-8+x)/3.0<<endl;
} 

Java :

import java.util.Scanner;

public class Main {
	 
    /**
     * @param args
     */
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = a * 3;
		int c = b - 8;
		double get = (double)(a+b+c)/3;
		System.out.println(b);
		System.out.println(c);
		System.out.println( String.format("%.1f", get));
		
	}
	public static void printArr(int [] a){
		for (int i = 0 ;i<= a.length - 1 ;i++) {
			System.out.print( a[i] + " ");
		}
	}
}

Python :

x = int(input())
a = x * 3
print(a)
b = a - 8
print(b)
su = x + a + b
print("%.1f" % (su / 3))