#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;
int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int tests;

    //cout << 9 % 5;
    //return 0;
    int colleges;
    cin >> tests;
    vector<vector <int> > data(tests);
    for (int i = 0 ; i < tests;i++){
        cin >> colleges;
        data[i] = vector<int>(colleges);
        int min;
        for (int n = 0; n < colleges; n++){
            int num;
            cin >> num;


            data[i][n] = num;
            if (data[i][n] < data[i][0])
                swap (data[i][n], data[i][0]);
        }
    }

    for (auto set : data ){
        int count = 0;


        // get floor!
        int floor=set[0];
        /*
        int counter1 =0;
        int counter2 =0;
        int counter3 =0;
        int counter4 =0;
        int counter0=0;


        for (auto number : set){
            int dif = number-floor;
            if (dif < 4)
                continue;
            if (dif % 5 == 4)
                counter4++;
            if (dif % 5 == 3)
                counter3++;
            if (dif % 5 == 2)
                counter2++;
            if (dif % 5 == 1)
                counter1++;
            if (dif % 5 == 0)
                counter0++;
        }
        cout << "floor = " << floor << endl;


        int floor_adj=(counter1 > counter0)?
                 ((counter2 > counter1)?
                    ((counter3 > counter2)?
                        ((counter4 > counter3)? 4
                        :3)
                     :2)
                 :1)
              :0;
        floor += floor_adj;
        cout << "floor = " << floor << " floor adj: " << floor_adj <<endl; */

        for (auto number : set){
            if (floor == number){
                continue;
            }
            int dif = number-floor;
            int mod = dif % 5;
            if (mod == 0 )
                count += dif/5;
            if (mod == 1 || mod == 2)
            {
                count += (dif-mod)/5 + 1;
            }
            if (mod == 3 || mod == 4)
            {
                count += (dif-mod)/5 + 2;
            }
            /*if (floor_adj > 1)
              count +=2;
            if (floor_adj ==1)
              count++; */
        }
        cout << count << endl;
    }
    return 0;
}