Игра на интервали

using System;

namespace КоледнаШапка
{
    class Program
    {
        static void Main(string[] args)
        {

            var gameTurns = int.Parse(Console.ReadLine());

            double points = 0;

            double first = 0;
            double second = 0;
            double third = 0;
            double fourth = 0;
            double fifth = 0;
            double inval = 0;

            for (int i = 0; i <= gameTurns; i++)
            {
                double turns = double.Parse(Console.ReadLine());

                if (turns < 0 || 50 < turns)
                {
                    inval++;
                    points /= 2.0;
                }
                else if (turns < 10)
                {
                    first++;
                    points = points + turns * 0.20;}
                else if (turns < 20)
                {
                    second++;
                    points = points + turns * 0.30;
                }
                else if (turns < 30)
                {
                    third++;
                    points = points + turns * 0.40;
                }
                else if (turns < 40)
                {
                    fourth++;
                    points = points + 50;
                }
                else if (turns <= 50)
                {
                    fifth++;
                    points = points + 100;
                }
                if (i == gameTurns -1)
                    break;
            }

            Console.WriteLine($"{points:f2}");

            first = first / gameTurns * 100;
            second = second / gameTurns * 100;
            third = third / gameTurns * 100;
            fourth = fourth / gameTurns * 100;
            fifth = fifth / gameTurns * 100;
            inval = inval / gameTurns * 100;

            Console.WriteLine($"From 0 to 9: {first:f2}%");
            Console.WriteLine($"From 10 to 19: {second:f2}%");
            Console.WriteLine($"From 20 to 29: {third:f2}%");
            Console.WriteLine($"From 30 to 39: {fourth:f2}%");
            Console.WriteLine($"From 40 to 50: {fifth:f2}%");
            Console.WriteLine($"Invalid numbers: {inval:f2}%");
        }
    }
}