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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int T; cin >> T;
    while(T--){
        long long N,M,K; cin >> N >> M >> K;
        if((N-1)*M < K){
            long long need = K-(N-1)*M;
            cout << fixed << setprecision(20) << 1-(need+0.0)/M << "\n";
        } 
        else{
            long long need = (K+M-1)/M;
            double answer = 1-(need+0.0)/N,left = 1-answer;
            answer += left/M*(M-1);
            cout << fixed << setprecision(20) << answer << "\n";
        }
    }
}