#pragma GCC optimize("Ofast")
#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <queue>
#include <cstdio>
#include <ctime>
#include <assert.h>
#include <chrono>
#include <random>
#include <numeric>
#include <set>
#include <deque>
#include <stack>
#include <sstream>
#include <utility>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <tuple>
#include <array>
#include <bitset>
using namespace std;
typedef long long int ll;
typedef unsigned long long ull;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) {
    return (ull)rng() % B;
}
inline double time() {
    return static_cast<long double>(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count()) * 1e-9;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int q; cin >> q;
    while(q--){
        long double T,u,l; cin >> T >> u >> l;
        long double L = 0, R = 5101;
        for(int _=0;_<100;_++){
            long double mid = (L+R)/2.0;
            long double v = mid*1000/60/60;
            if(v*T+v*v/20/u <= l + 1e-9){
                L = mid;
            }
            else{
                R = mid;
            }
        }
        int r = floor(L*100);
        printf("%.2f\n",r/100.0);
    }
}