using System;

​

public class Program {

    public static void Main() {

        double[] precos = new double[6];

        double soma = 0;

        for(int i = 0; i < 6; i++) {

            Console.Write("Introduza o preço " + (i+1) + ": ");

            precos[i] = double.Parse(Console.ReadLine());

            soma += precos[i];

        }

        Console.WriteLine("\nA soma=: " + soma);

        Console.WriteLine("A média=: " + (soma/6));

        Console.WriteLine("\nO dobro=: ");

        for(int i = 0; i < 6; i++) {

            Console.WriteLine((i+1) + ": " + (2*precos[i]));

        }

    }

}

​