#include <bits/stdc++.h>
#define int long long
#define endl "\n"
using namespace std;

void solve()
{
    int n,m,k;cin>>n>>m>>k;
    long double deno = n*m;
    long double num = 0;
    if (k>(n-1)*m)
    {
        num = n-1 + (k-(n-1)*m);
    }
    else
    {
        num = (k+m-1)/m;
    }

    cout << 1.0 - num/deno << endl;
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout<<setprecision(15)<<fixed;

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