#include <iostream>
#include <fstream>
#include <cstdio>
#include <sstream>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <string>
#include <map>
#include <vector>
#include <set>
#include <queue>
#include <deque>
#include <ctime>
#include <cstdlib>

using namespace std;

#define sz(x) ((int)((x).size()))

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;

const double EPS = 1e-9;
const int MAXN = (int)(1e5) + 10;

int n, pw;
int vw[MAXN], pf[MAXN], vf[MAXN], th[MAXN];

double getF(double W) {
	double res = W * pw;
	for (int i = 0; i < n; i++) {
		double f = max(th[i] - W * vw[i], 0.0);
		f /= vf[i];
		res += f * pf[i];
	}
	return res;
}

void solve() {
	scanf("%d", &pw);
	for (int i = 0; i < n; i++) {
		scanf("%d%d%d%d", &vw[i], &pf[i], &vf[i], &th[i]);
	}
	int id = 0;
	double res = getF(0);
	for (int i = 1; i < 500; i++) {
		double cur = getF(i + 0.0);
		if (res > cur) {
			res = cur;
			id = i;
		}
	}
	res = (1e18);
	if (id > 0) {
		double lf = id - 1.0;
		double rg = id;
		for (int it = 0; it < 100; it++) {
			double md1 = (2.0 * lf + rg) / 3.0;
			double md2 = (lf + 2.0 * rg) / 3.0;
			if (getF(md1) > getF(md2))
				lf = md1;
			else
				rg = md2;
		}
		res = min(res, getF(lf));
	}
	double lf = id;
	double rg = id + 1.0;
	for (int it = 0; it < 100; it++) {
		double md1 = (2.0 * lf + rg) / 3.0;
		double md2 = (lf + 2.0 * rg) / 3.0;
		if (getF(md1) > getF(md2))
			lf = md1;
		else
			rg = md2;
	}
	res = min(res, getF(lf));
	printf("%.12lf\n", res);
}

int main() {
	//freopen(".in", "r", stdin);
	//freopen(".out", "w", stdout);

	while (scanf("%d", &n) == 1 && n != 0) {
		solve();
	}

	return 0;
}
