#include <bits/stdc++.h>
using namespace std;
using ld = long double;
int main(void){
    int t;
    cin>>t;
    while(t--){
        long long n,m,k;
        cin>>n>>m>>k;
        if(k<=(n-1)*m){
            long long ck=k/m+(bool)(k%m);
            cout << fixed << setprecision(15) <<((ld)ck*(ld)(m-1)/((ld)n*(ld)m))+((ld)(n-ck)/(ld)n)<<endl;
        }else{
            cout << fixed << setprecision(15) <<(ld)(k-(n-1)*m)/(ld)m<<endl;
        }
    }
    return 0;
}