import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;

public class Main {
    static double cache[][];
    static int n, m;
    static int MAX = 2000;

    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuffer sb = new StringBuffer();

        int test = Integer.parseInt(br.readLine().trim());

        while (test-- > 0) {
            String s[] = br.readLine().split(" ");
            // 우물 깊이
            n = Integer.parseInt(s[0]);
            // 비온날
            m = Integer.parseInt(s[1]);
            cache = new double[MAX][MAX];

            init();

            System.out.printf("%.10f\n", climb(0, 0));

        }
    }

    static void init() {
        for (double[] arr : cache)
            Arrays.fill(arr, -1);
    }

    public static double climb(int meter, int days) {

        if (days == m && days != 0)
            return meter >= n ? (double) 1.0 : (double) 0.0;

        if (cache[meter][days] >= 0)
            return cache[meter][days];

        return cache[meter][days] = (0.75 * climb(meter + 2, days + 1)) + (0.25 * climb(meter + 1, days + 1));
    }
}