#include <iostream>
#include <iomanip>
using namespace std;

double climb(int day, int climbed, int deadline, int depth, double** cache)
{
    if (day == deadline) {
        return (climbed >= depth) ? (1) : (0);
    }

    double& ret = cache[day][climbed];
    if (ret != -1) {
        return ret;
    }

    return ret = 0.25 * climb(day+1, climbed+1, deadline, depth, cache) 
               + 0.75 * climb(day+1, climbed+2, deadline, depth, cache);
}

void solveCase(void)
{
    int depth = 0;
    int deadline = 0;
    cin >> depth >> deadline;

    double** cache = new double*[deadline];
    for (int i = 0; i< deadline; i++)
    {
        cache[i] = new double[deadline*2 + 1];
    }

    for (int i = 0; i< deadline; i++)
    {
        for (int j = 0; j< deadline*2 +1; j++)
        {
            cache[i][j] = -1;
        }
    }

    double answer = climb(0, 0, deadline, depth, cache);
    cout.precision(10);
    cout.setf(ios::fixed, ios::floatfield);
    cout << answer << endl;
}

int main(void)
{
    int cases=0;
    cin >> cases;
    while(cases--)
    {
        solveCase();
    }
    return 0;
}