Encapsulation and abstration, C#

Language: Layout:

//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Bike
    {
       public int mileage = 65;
       public string color = "Black";
       private string formula="a*b" ;
       //Its public – so accessible outside class
       public int GetMileage()
       {
               return mileage;
       }

//Its public – so accessible outside class
       public string GetColor()
       {
               return color;
       }

//Its private – so not accessible outside class
       private string GetEngineMakeFormula()
       {
               return formula;
       }

//Its public – so accessible outside class
       public string DisplayMakeFormula()
       {
               //"GetEngineMakeFormula()" is private but accessible and limited to this class only
               return GetEngineMakeFormula();
       }
    }
    public class Program
    {
        public static void Main(string[] args)
        {
               Bike objBike = new Bike();
                
               Console.WriteLine("Bike mileage is : " + objBike.GetMileage()); //accessible outside "Bike"
               Console.WriteLine("Bike color is : " + objBike.GetColor()); //accessible outside "Bike"
               //we can't call this method as it is inaccessible outside "Bike"
               //objBike.GetEngineMakeFormula(); //commented because we can't access it
               Console.WriteLine("Bike formula is : " + objBike.DisplayMakeFormula()); //accessible outside
        }
    }
}

Show compiler warnings [ + ] Show input