#include<stdio.h>
#include<algorithm>
#include<string.h>

double cache[1005][2005];
int n, m;

double count(int days, int sum)
{
    if (days == m)
        return sum >= n ? 1 : 0;
    double& ret = cache[days][sum];
    if (ret != -1)
        return ret;
    return ret = 0.25 * count(days + 1, sum + 1) + 0.75 * count(days + 1, sum + 2);
}
int main(void)
{
    memset(cache, -1, sizeof(cache));
    int C;
    scanf("%d", &C);
    for (int tc = 0; tc < C; tc++)
    {
        scanf("%d %d", &n, &m);
        printf("%.10f\n", count(0,0));
    }
    return 0;
}