prob6.cpp

/*
	Problem 6: Drizzle
	from the Mercer 2018 Spr Programming contest

	Charles Bailey
	03 02 2018
*/
#include <bits/stdc++.h>

typedef long long ll;

const double EPI = 1e-6;

struct bg_speed_point {
	double point;
	bool is_left;
	ll id;

	bool operator<(const bg_speed_point& o) const {
		if (point > o.point)
			return true;
		if (std::abs(o.point - point) <= EPI) {
			if (id != o.id) return !is_left;
			return is_left;
		}

		return false;
	}
};

static void one_case(void) {
	ll n, x, vmax;
	std::scanf("%lld %lld %lld",&n,&x,&vmax);

	std::multiset<bg_speed_point> stuff;

	double local_max = 0;
	for (ll i = 0; i < n; ++i) {
		double xi,yi,li,vi;
		std::scanf("%lf %lf %lf %lf",&xi,&yi,&li,&vi);

		double t1 = yi/vi;
		double t2 = (yi + li) / vi;

		stuff.insert({xi / t1, true, i});
		stuff.insert({xi / t2, false, i});

		local_max = std::max(local_max,  std::max(xi/t1, xi/t2));
	}

	double vmaxd = vmax;
	stuff.insert({vmaxd, true, n});
	stuff.insert({vmaxd, false, n});

	double ans = 0;
	ll cnt = 0;
	if (local_max < vmax)
		ans = vmax;
	for (auto& e : stuff) {
		// std::printf("%s of interval at v = %f (id = %lld)\n", e.is_left ? "OPEN" :"CLOSE", e.point, e.id);
		if (cnt == 0 && e.point <= vmaxd) {
			ans = std::max(ans,e.point);
		}
		cnt += e.is_left ? 1 : -1;
		if (cnt == 0 && e.point <= vmaxd) {
			ans = std::max(ans,e.point);
		}
	}
	// std::printf("----\n");
	// std::printf("speed: %f\n", ans);
	std::printf("%f\n", x / ans);
}

int main(void) {
	ll t;
	std::scanf("%lld", &t);
	while(t--) one_case();
	return 0;
}