#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
const long long mod=998244353;
const long long mod2=469762049;
void solve(){
    ll N,M,K;cin>>N>>M>>K;
    cout<<fixed<<setprecision(15);
    if(K<=(N-1)*M+1){
        long double res=1;
        ll cnt=(K+M-1)/M;
        res/=N;
        res/=M;
        res*=cnt;
        res=1-res;
        cout<<res<<endl;
        return;
    }
    else{
        ll cnt=N*M-K;
        long double res=1;
        res/=M;
        res*=cnt;
        cout<<res<<endl;
        return;
    }
}
int main(){
    cin.tie(0)->sync_with_stdio(0);
    cout.tie(0);
    int T;cin>>T;
    while(T--) solve();
}