#include<bits/stdc++.h>

using namespace std;
using ll=long long;

ll to_long_long(string X){
    int n=X.length();
    return stol(X.substr(0,n-3))*100+(X[n-2]-'0')*10+(X[n-1]-'0');
}

bool check(ll V, ll T, ll mu, ll L){return V*(25*V+18*T*mu)<=(ll)6480*mu*L;}

string answer(int V){
    int x=V/100, y=V%100;
    int a=y/10, b=V%10;
    return to_string(x)+"."+to_string(a)+to_string(b);
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    string t,m,l;
    ll T,mu,L;
    int D,U,M;

    int N; cin >> N;

    while (N){
        cin >> t >> m >> l;
        T=to_long_long(t);
        mu=to_long_long(m);
        L=to_long_long(l);

        D=0; U=5100*100;
        while (U-D>1){
            M=D+(U-D)/2;
            if (check(M,T,mu,L)){
                D=M;
            }else{
                U=M;
            }
        }

        cout << answer(D) << "\n";

        N--;
    }

    return 0;
}