#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <cmath>
#include <ctime>
#include <cassert>

using namespace std;

#define pb push_back
#define mp make_pair
#define sz(A) (int)(A).size()

typedef long long LL;
typedef long double LD;

const int N = int(1e5 + 5), M = 55;

LD dp[N][M];

int main() {
    int t;
    scanf("%d", &t);

    for (int i = 0; i < N; i++)
        dp[i][0] = i;

    for (int j = 1; j < M; j++) {
        LD sum = 0;
        for (int i = 0; i < N; i++) {
            if (i)
                dp[i][j] = sum / i;
            sum += dp[i][j - 1];
        }
    }

    for (int i = 0; i < t; i++) {
        int n, k;
        scanf("%d%d", &n, &k);
        if (k >= M)
            printf("%.6lf\n", 0.0);
        else
            printf("%.6lf\n", double(dp[n][k]));
    }

    return 0;
}