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

using ll = long long;

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

    int T;
    cin >> T;

    cout << fixed << setprecision(15);

    while (T--) {
        ll N, M, K;
        cin >> N >> M >> K;

        long double ans;
        ll border = (N - 1) * M + 1;

        if (K <= border) {
            ll t = (K + M - 1) / M;  // ceil(K / M)
            ans = 1.0L - (long double)t / ((long double)N * M);
        } else {
            ans = (long double)(N * M - K) / M;
        }

        cout << ans << '\n';
    }

    return 0;
}