#include <bits/stdc++.h>
using namespace std;
long double f(int x, long double Q, long double R, int remain, long double p)
{
  long double a = (remain - x) * (Q - (1.0 - p) * R);  // もみ消す
  long double b = Q * ((1.0 - pow(p, x)) / (1.0 - p)); // クビになる(ゼロ除算に注意)
  return a + b;
}
long double g(int x, long double Q, long double R, int remain, long double p)
{
  long double a = -Q + (1 - p) * R;
  long double b = Q * pow(p, x);
  return a + b;
}
#pragma GCC optimize("O3")
int main()
{
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  auto solve = []()
  {
    int N, X, Y;
    cin >> N >> X >> Y;
    long double P, Q, R;
    cin >> P >> Q >> R;
    long double ans = -1.0;
    for (int t = 0; t <= N; t++)
    {
      int skill = X + t * Y;
      long double p = 1.0 - 1.0 / skill;
      int remain = N - t;
      if (skill == 1)
      { // 必ず卵をかけてしまう場合
        if (remain == 1)
        {
          ans = max(ans, P * t + Q);
        }
        else
        {
          ans = max(ans, P * t + (Q - R) * (remain - 1) + Q);
        }
        continue;
      }
      int left = 0, right = remain;
      while (1 < right - left)
      {
        int mid = (left + right) / 2;
        if (g(mid, Q, R, remain, p) < 0)
        {
          right = mid;
        }
        else
        {
          left = mid;
        }
      }
      ans = max(ans, P * t + f(right, Q, R, remain, p));
    }
    cout << fixed << setprecision(15) << ans << endl;
  };
  int T;
  cin >> T;
  for (int i = 0; i < T; i++)
  {
    solve();
  }
}