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



int main()
{
    long long int n,i,j,k,t;
    string s;
    cin>>t;
    while(t--)
    {
        cin>>n>>s;
        double arr[n+5],sum=0.0;
        for(i=0;i<n;i++)
        {
            cin>>arr[i];
            if(arr[i]==0)
                continue;
            arr[i]/=100;
            if(s=="bit")
                sum+=(arr[i]*log2(arr[i]));
            else if(s=="nat")
                sum+=(arr[i]*log(arr[i]));
            else if(s=="dit")
               sum+=(arr[i]*log10(arr[i]));
        }
        sum*=-1;
        printf("%.12lf\n",sum);
    }
    return 0;
}