using System;

public class Program

{

    public static void Main()

    {

        double min = 0;

        double max = 100;

​

        for (double a = min; a <= max; a++)

        {

            for (double b = min; b <= max; b++)

            {

                for (double c = min; c <= max; c++)

                {

                    for (double d = min; d <= max; d++)

                    {

                        if(a + b + c == 100 && a + 10 * b + 50 * c == 500)

                        {

                            Console.WriteLine("a=" + a + ", b=" + b + ", c=" + c + ", d=" + d);

                        }

                    }

                }

            }

        }

    }

}