Problem P

#include<bits/stdc++.h>
using namespace std;

const double eps = 1e-9;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int t;
    cin >> t;
    while(t--)
    {
        int n, k;
        cin >> n >> k;
        vector<int> arr(n);
        for(int &x : arr)
            cin >> x;

        double perc = double(k) / 100.0;
        double lo = 0, hi = 1e6, ans = 0;

        for(int itr = 0; itr < 100; itr++)
        {
            double mid = (lo + hi) / 2;
            double need = 0, have = 0;
            for(int i = 0; i < n; i++)
            {
                if(arr[i] > mid)
                    have += arr[i] - mid;
                else
                    need += (mid - arr[i]) / (1 - perc);
            }

            if(need <= have)
                ans = lo = mid;
            else
                hi = mid;
        }

        cout << setprecision(10) << fixed << ans << endl;
    }
}