#include <bits/stdc++.h>

#include <atcoder/all>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define FAST_IO                \
  ios::sync_with_stdio(false); \
  cin.tie(0);
const i64 INF = 1001001001001001001;

using Modint = atcoder::static_modint<998244353>;
vector<vector<Modint>> enumFIF(int n) {
  vector fif(2, vector(n + 1, Modint(0)));
  fif[0][0] = 1;
  for (auto i : views::iota(1, n + 1)) {
    fif[0][i] = fif[0][i - 1] * i;
  }
  fif[1][n] = fif[0][n].inv();
  for (auto i = n; i > 0; i--) {
    fif[1][i - 1] = fif[1][i] * i;
  }
  return fif;
}

Modint comb(int n, int r, vector<vector<Modint>>& fif) {
  return fif[0][n] * fif[1][r] * fif[1][n - r];
}


int main() {
  FAST_IO

  int T;
  cin >> T;


  while (T--) {
    i64 N, M;
    i64 K;
    cin >> N >> M >> K;

    // x * M >= K
    i64 x = (K + M - 1) / M;
    double ans = 0;
    if (x < N) {
      // N-1Cx-1/NCx * 1/M
      // / x /MN

      double y = 1.0 * x / N / M;
      ans = 1.0 - y;
    } else {
      i64 z = K - (N - 1) * M;

      // M-1Cx-1/MCx = x/M
      double y = 1.0 * z / M;
      ans = 1.0 - y;
    }
    cout << setprecision(15) << fixed << ans << endl;
  }
}