Here's the simple java solution
IntuitionApproachComplexity
Time complexity: O(n^2)

Space complexity: O(1)
Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity: O(n^2)
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity: O(1)
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```java []
class Solution {
    public int countPairs(int[] nums, int k) {
        int count=0;
        for(int i=0;i<nums.length-1;i++){
            for(int j=i+1;j<nums.length;j++){
                if(nums[i]==nums[j]){
                    if((i*j)%k==0){
                        count++;
                    }
                }
            }
        }
        return count;
    }
}
```
['Java']