#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

#define ll long long

using namespace std;

const int N=;

int T,n,m;ll jc[N],s[N][N];

void init()

{

  jc[]=;for(int i=;i<=;i++)jc[i]=jc[i-]*i;

  s[][]=;

  for(int i=;i<=;i++)

    for(int j=;j<=i;j++)

      s[i][j]=s[i-][j]*(i-)+s[i-][j-];

}

int main()

{

  init();

  scanf("%d",&T);

  while(T--)

    {

      scanf("%d%d",&n,&m);

      ll ans=;

      for(int i=;i<=m;i++)ans+=s[n][i]-s[n-][i-];

      printf("%.4f\n",(double)ans/jc[n]);

    }

  return ;

}