creating score point for 3 objects

Hi, i'm doing a game which the player collect money 5,10,20 and each one have different score, i wrote the code but the errors don't show up and the score doesn't change .. please can anyone help me! i using C#

 private int Money5=0;
      private int Money10=0;
      private int Money20=0;
      private float timeleft=60;
      private int Scores=0;
      
      // Use this for initialization
      void Start () {
      
      }
      
      // Update is called once per frame
      void FixedUpdate () {
             timeleft = timeleft - Time.deltaTime;
      Scores = Money5 + Money10 + Money20;
          
      }
      
      // we must put a tick next to the trigger in the unity of the prefab
      void OnTriggerEnter(Collider other)
      {
          // the name pickUp should be the same in the unity of the prefab in the tag
          if (other.gameObject.tag == "money5") {
              other.gameObject.SetActive(false);
              Scores = 5 + Scores; // to make the score increasing by 5
              Destroy (other.gameObject);
          }
          if (other.gameObject.tag == "money10") {
              other.gameObject.SetActive(false);
              Scores = 10 + Scores; // to make the score increasing by 10
              Destroy (other.gameObject);
          }
          if (other.gameObject.tag == "money20") {
              other.gameObject.SetActive(false);
              Scores = 20 + Scores; // to make the score increasing by 20
              Destroy (other.gameObject);
          }
          
 void OnGUI() {
             
             string Scors = Scores.ToString ();
         GUI.Box (new Rect (190, 10, 70, 50), "Scores");
         GUI.Label (new Rect (190, 30, 150, 20),Scors);
         }
          
      }