#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
const int N = 2000010, MOD = 998244353, INF = 0x3f3f3f3f;
int n, m, w[N];


ll k;
void solve() {
    scanf("%d%d%lld", &n, &m, &k);
    if (k <= (n - 1ll) * m) {
        printf("%.14lf\n", (n - (k + m - 1) / m) / (double)n + (k + m - 1) / m / (double)n * (m - 1) / m);
    } else {
        printf("%.14lf\n", (m - (k - (n - 1ll) * m)) / (double)m);
    }
}


int main() {
    int T;
    cin >> T;
    while (T--) solve();
    return 0;
}