how to reset timer when score hits an increment of 50

say you have a score script that keeps score using UnityEngine; using UnityEngine.UI; using System.Collections;

 public class Score : MonoBehaviour 
 {
     public Text scoreGUI;
     public int scoreCounter;
 
 
     // Use this for initialization
     void Awake () 
     {
         scoreGUI = GetComponent <Text> ();
         scoreCounter = 0;
     }
     
     // Update is called once per frame
     void Update () 
     {
         scoreGUI.text = "Score: " + scoreCounter;
     }
 
 
 }

(currents in another Script i have the script so it adds a point every time a certain object is clicked, so that works)

Before i go on, here is my timer script. it counts down from 10 to 0 and on 0 it will stop counting down and it will end the game

 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
 
 public class TimerGUI : MonoBehaviour 
 {
     public Text timerGUI;
     public int timer;
     
     // Use this for initialization
     void Awake () 
     {
         timerGUI = GetComponent <Text> ();
         timer = 0;
     }
     
     // Update is called once per frame
     void Update () 
     {
         if (timer > 0) 
         {
             timer -= Time.deltaTime;
         }
 
         if (timer = 0) 
         {
             //lose game.
         }
 
         timerGUI.text = "Time Left: " + timer;
     }
 }

What ive been trying to do is figure out how i can have the timer reset to 10 every time the scoreCounter reaches an increment of 50 (50,100,150, and so on) but i cant figure out how. i know how to do it say if it would hit 50

if (score.scoreCounter = 50) { timer = 0; }

but i cant figure out how to make it reset like that every time the score hits an increment of 50.

Help would be appreciated, thanks!