#include <stdio.h>
float Cache[2001][1001];
unsigned int n;
float escape(int depth, int day) {
    float *ret = &Cache[depth][day];
    if (day == 0)
    {
        return *ret = depth >= n ? 1 : 0;
    }
    else
    {
        if (*ret != -1)
        {
            return *ret;
        }
        else
        {
            return *ret = 0.25*escape(depth + 1, day - 1) + 0.75*escape(depth + 2, day - 1);
        }
    }
}

int main() {
    unsigned int C;
    scanf("%d", &C);
    while (C)
    {
        float *p = Cache;
        float *q = p + 2001*1001-7;
        for (p = Cache; p < q; p += 8)
        {
            *(p) = *(p + 1) = *(p + 2) = *(p + 3) = *(p + 4) = *(p + 5) = *(p + 6) = *(p + 7) = -1;
        }

        scanf("%d", &n);
        unsigned int m;
        scanf("%d", &m);
        printf("%.10f\n", escape(0, m));
        --C;
    }
    return 0;
}