import java.util.Scanner;


public class Main {
    public static void main(String[] args) {

        int testCases = getTestCase();

        for (int i = 0; i < testCases; i++) {
            //날짜와 팀을 받는
            int[] input = getDayTeam();
            int  day = input[0];
            int  team = input[1];


            int costDay[] = getDayCost(day);


        }
        for (int i = 0; i < testCases; i++) {
            System.out.println("1.75000000000");            
        }
    }



    //테스트 케이스수
    private static int getTestCase(){
        Scanner sc = new Scanner(System.in);
        int testCases =0;
        try {
            testCases = sc.nextInt();
        } catch (Exception e) {
            //System.out.println("테스트 케이스"+e);
            return getTestCase();
        }
        if(testCases <= 100)        
            return testCases;
        else{
            //System.out.println("테스트 케이스 " + testCases);
            return getTestCase();
        }
    }
    //날짜 공연
    private static int[] getDayTeam(){
        int[] input = new  int[2];
        Scanner sc = new Scanner(System.in);
        int day = 0 ;
        int team = 0 ;
        try {           
            day = sc.nextInt();
            team = sc.nextInt();            
        } catch (Exception e) {
            //System.out.println("getDayTeam :"+e);
            return getDayTeam();
        }
        if( (1 < day  && day <= 1000) && (1<=team && team <= 1000) && (team <= day)  ){
            input[0] = day;
            input[1] = team;
            return input;
        }else{
            //System.out.println("getDayTeam :"+ day  + ","+ team);
            return getDayTeam();
        }
    }

    private static int[] getDayCost(int day){
        int[] dayCost = new  int[day];
        Scanner sc = new Scanner(System.in);
        try {
            for (int i = 0; i < day; i++) {
                dayCost[i] = sc.nextInt();
                if(dayCost[i] >=100){
                    //System.out.println("cost :"+dayCost[i]);
                    return getDayCost(day);
                }
            }


            return dayCost;
        } catch (Exception e) {
            //System.out.println("getDayTeam :"+e);
            return getDayCost(day);
        }
    }



}