#include<bits/stdc++.h>
using namespace std;

void solve(){
  using ll=long long;
  ll n,m,k;
  cin>>n>>m>>k;
  double ans=0;
  if ((n-1)*m>=k){
    ll q=(k+m-1)/m;
    ans+=(double)q/n*(m-1)/m;
    ans+=(double)(n-q)/n;
  }
  else{
    k-=(n-1)*m+1;
    ans=(double)(m-1-k)/m;
  }
  cout<<fixed<<setprecision(10);
  cout<<ans<<endl;
}

int main(){
  int t;
  cin>>t;
  while (t--) solve();
}