#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)
#define all(x) begin(x), end(x)
template <class T> bool chmin(T& x, T y) {
	return x > y ? (x = y, true) : false;
}
template <class T> bool chmax(T& x, T y) {
	return x < y ? (x = y, true) : false;
}

void solve() {
	ll n, m, k;
	cin >> n >> m >> k;
	ll dv = (k + m - 1) / m;
	if (dv >= n) {
		ll d = k - (n - 1) * m;
		cout << (double)(m - d) / m << '\n';
	} else {
		double d = 0;
		d += (double)(n - dv) / n;
		d += ((double)dv / n) * (m - 1) / m;
		cout << d << '\n';
	}
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout << fixed << setprecision(15);
	int t = 1;
	cin >> t;
	while (t--) solve();
}