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

const double EPS = 1e-6;

double S(double v, double t, double m) {
    return v * t + v * v / (20 * m);
}

bool check(double V, double t, double m, double l) {
    double v = 5 * V / 18;
    return (S(v, t, m) - EPS < l);
}

int main() {
    int N;
    cin >> N;
    for (int i = 0; i < N; ++i) {
        double T, mu, L;
        cin >> T >> mu >> L;
        double ok = 0, ng = 5100;
        for (int j = 0; j < 100; ++j) {
            double m = (ok + ng) / 2;
            if (check(m, T, mu, L)) ok = m;
            else ng = m;
        }
        cout << fixed << setprecision(2) << (int)(ok * 100) / 100.0 << endl;
    }
}