using System;

string zero = "0";

​

for(int x = 1; x<10;x++){

  for(int y =1; y<10;y++){

      string a = x.ToString();

      string b = y.ToString();

      string m1 = a+b;

      string m2 = b+a;

      string m3 =a+zero+b;

      int m1int = Convert.ToInt32(m1);

      int m2int = Convert.ToInt32(m2);

      int m3int = Convert.ToInt32(m3);

      for (int z = 0; z <100; z++){

          if (m3int - z == m2int && m2int - z == m1int)

              Console.WriteLine($"Speed is {z} mph: M1 is {m1} M2 is {m2} and M3 is {m3}");

​

} 

}

}