#if __INCLUDE_LEVEL__ == 0

#include __BASE_FILE__

void Solve() {
  int64_t n, m, k;
  IN(n, m, k);
  double ans = 0.0;
  /* for (int64_t x = 1; x <= n; ++x) {
    if (k <= (x - 1) * m) {
      ans += 1.0;
    } else if (k <= (n - 1) * m + 1) {
      ans += double(m - 1) / double(m);
    } else {
      ans += double(m - 1) / double(m) * (1.0 - double(k - (n - 1) * m - 1) / (double(m - 1)));
    }
  } */
  int64_t X = DivCeil(k, m);
  ans += double(n - X);
  if (k <= (n - 1) * m + 1) {
    ans += double(m - 1) / double(m) * X;
  } else {
    ans += double(m - 1) / double(m) * (1.0 - double(k - (n - 1) * m - 1) / (double(m - 1))) * X;
  }
  ans /= double(n);
  OUT(ans);
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout << setprecision(DBL_DECIMAL_DIG);

  int t;
  IN(t);
  while (t--) {
    Solve();
  }
}

#elif __INCLUDE_LEVEL__ == 1

#include <bits/stdc++.h>

template <class T>
concept MyRange =
    std::ranges::range<T> &&
    !std::convertible_to<T, std::string_view> &&
    !std::convertible_to<T, std::filesystem::path>;

template <class T>
concept MyTuple = std::__is_tuple_like<T>::value && !MyRange<T>;

namespace std {

istream& operator>>(istream& is, MyRange auto&& r) {
  for (auto&& e : r) {
    is >> e;
  }
  return is;
}

istream& operator>>(istream& is, MyTuple auto&& t) {
  apply([&](auto&... xs) { (is >> ... >> xs); }, t);
  return is;
}

ostream& operator<<(ostream& os, MyRange auto&& r) {
  auto sep = "";
  for (auto&& e : r) {
    os << exchange(sep, " ") << forward<decltype(e)>(e);
  }
  return os;
}

ostream& operator<<(ostream& os, MyTuple auto&& t) {
  auto sep = "";
  apply([&](auto&... xs) { ((os << exchange(sep, " ") << xs), ...); }, t);
  return os;
}

}  // namespace std

template <class T>
class OneBased {
 public:
  explicit OneBased(T&& x) : ref_(std::forward<T>(x)) {}

  template <class... Ts>
  requires(sizeof...(Ts) > 1)
      OneBased(Ts&&... xs) : ref_(std::forward_as_tuple(std::forward<Ts>(xs)...)) {}

  friend std::istream& operator>>(std::istream& is, OneBased x) {
    if constexpr (MyRange<T>) {
      for (auto&& e : x.ref_) {
        is >> ::OneBased(e);
      }
    } else if constexpr (MyTuple<T>) {
      std::apply([&](auto&... xs) { (is >> ... >> ::OneBased(xs)); }, x.ref_);
    } else {
      is >> x.ref_;
      --x.ref_;
    }
    return is;
  }

  friend std::ostream& operator<<(std::ostream& os, OneBased x) {
    if constexpr (MyRange<T>) {
      auto f = [](auto&& e) { return ::OneBased(std::forward<decltype(e)>(e)); };
      os << (x.ref_ | std::views::transform(f));
    } else if constexpr (MyTuple<T>) {
      std::apply([&](auto&... xs) { os << std::tuple(::OneBased(xs)...); }, x.ref_);
    } else {
      os << ++x.ref_;
      --x.ref_;
    }
    return os;
  }

 private:
  T ref_;
};

template <class T>
OneBased(T&&) -> OneBased<T>;

template <class... Ts>
OneBased(Ts&&...) -> OneBased<std::tuple<Ts...>>;

using namespace std;

#define LAMBDA2(x, y, ...) ([&](auto&& x, auto&& y) -> decltype(auto) { return __VA_ARGS__; })
#define DivCeil(...) LAMBDA2(x, y, x / y + ((x ^ y) >= 0 && x % y))(__VA_ARGS__)
#define IN(...) (cin >> forward_as_tuple(__VA_ARGS__))
#define OUT(...) (cout << forward_as_tuple(__VA_ARGS__) << '\n')

#endif  // __INCLUDE_LEVEL__ == 1