#include <algorithm>
#include <bitset>
#include <climits>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>

#define MOD 1000000007
#define MOD2 998244353
#define int long long
#define EPS 1e-9
//#define PI 3.14159265358979

#define rep(i, n) for (int i = 0; i < (int)(n); i++)

using namespace std;

template < typename T >
ostream &operator<<(ostream &os, const vector< T > &A) {
	for (int i = 0; i < A.size(); i++)
		os << A[i] << " ";
	os << endl;
	return os;
}
template <>
ostream &operator<<(ostream &os, const vector< vector< int > > &A) {
	int N = A.size();
	int M;
	if (N > 0)
		M = A[0].size();
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < M; j++)
			os << A[i][j] << " ";
		os << endl;
	}
	return os;
}

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

struct edge {
	int from, to, d, c;
	edge(int _from = 0, int _to = 0, int _d = 0, int _c = 0) {
		from = _from;
		to = _to;
		d = _d;
		c = _c;
	}
	bool operator<(const edge &rhs) const {
		return (d == rhs.d) ? (c < rhs.c) : (d < rhs.d);
	}
};
struct aabb {
	int x1, y1, x2, y2;
	aabb(int x1, int y1, int x2, int y2) : x1(x1), y1(y1), x2(x2), y2(y2) {}
};

typedef vector< edge > edges;
typedef vector< edges > graph;
struct flow {
	int to, cap, rev, cost;
	flow(int to = 0, int cap = 0, int rev = 0, int cost = 0) : to(to), cap(cap), rev(rev), cost(cost) {}
};
typedef vector< vector< flow > > flows;

const int di[4] = {0, -1, 0, 1};
const int dj[4] = {-1, 0, 1, 0};
const int ci[5] = {0, 0, -1, 0, 1};
const int cj[5] = {0, -1, 0, 1, 0};
const ll LINF = LLONG_MAX / 2;
const int INF = INT_MAX / 2;
const double PI = acos(-1);

int pow2(int n) { return 1LL << n; }
template < typename T, typename U >
bool chmin(T &x, const U &y) {
	if (x > y) {
		x = y;
		return true;
	}
	return false;
}
template < typename T, typename U >
bool chmax(T &x, const U &y) {
	if (x < y) {
		x = y;
		return true;
	}
	return false;
}

struct initializer {
	initializer() {
		cout << fixed << setprecision(20);
	}
};
initializer _____;
struct point {
	double x, y;
	int i;
	point(double x = 0.0, double y = 0.0) : x(x), y(y) {}
	point operator+(const point &rhs) const {
		return point(x + rhs.x, y + rhs.y);
	}
	point operator-(const point &rhs) const {
		return point(x - rhs.x, y - rhs.y);
	}
	point operator-() { return point(-x, -y); }
	point operator*(const double d) const {
		return point(x * d, y * d);
	}
};
double dot(const point &a, const point &b) {
	return a.x * b.x + a.y * b.y;
}
double det(const point &a, const point &b) {
	return a.x * b.y - a.y * b.x;
}
double arg(const point &a) {
	return atan2(a.y, a.x); //[-PI,PI)
}
double abs(const point &a) {
	return sqrt(a.x * a.x + a.y * a.y);
}
int ccw(point &a, point &b, point &c) {
	if (det(b - a, c - a) > EPS)
		return 1;
	if (det(b - a, c - a) < -EPS)
		return -1;
	return 0;
}
point Orthgonal(const point &a) {
	return point(a.y, -(a.x));
}
struct circle {
	double r, x, y;
	circle(double r = 0.0, double x = 0.0, double y = 0.0) : r(r), x(x), y(y) {}
	circle(double r, point p) : r(r), x(p.x), y(p.y) {}
	point getCenter() { return point(x, y); }
};
double dist(point a, point b) {
	double x = a.x - b.x;
	double y = a.y - b.y;
	return sqrt(x * x + y * y);
}
bool getCircle(point p1, point p2, double r, point &pc1, point &pc2) {
	bool stat = true;
	point p3;
	double d, l, dx, dy;
	p3.x = (p1.x + p2.x) * 0.5;
	p3.y = (p1.y + p2.y) * 0.5;
	r *= r;
	l = (p2.x - p3.x) * (p2.x - p3.x) + (p2.y - p3.y) * (p2.y - p3.y);
	if (r >= l) {
		d = sqrt(r / l - 1.0);
		dx = d * (p2.y - p3.y);
		dy = d * (p2.x - p3.x);

		pc1.x = p3.x + dx;
		pc1.y = p3.y - dy;

		pc2.x = p3.x - dx;
		pc2.y = p3.y + dy;
	} else {
		stat = false;
	}

	return stat;
}
circle getCircle(point &p1, point &p2, point &p3) {
	double ox, oy, a, b, c, d, r1, r2, r3;
	a = p2.x - p1.x;
	b = p2.y - p1.y;
	c = p3.x - p1.x;
	d = p3.y - p1.y;
	circle ret;
	if (ccw(p1, p2, p3) != 0) {
		ox = p1.x + (d * (a * a + b * b) - b * (c * c + d * d)) / (a * d - b * c) / 2;
		if (b) {
			oy = (a * (p1.x + p2.x - ox - ox) + b * (p1.y + p2.y)) / b / 2;
		} else {
			oy = (c * (p1.x + p3.x - ox - ox) + d * (p1.y + p3.y)) / d / 2;
		}
		r1 = sqrt((ox - p1.x) * (ox - p1.x) + (oy - p1.y) * (oy - p1.y));
		r2 = sqrt((ox - p2.x) * (ox - p2.x) + (oy - p2.y) * (oy - p2.y));
		r3 = sqrt((ox - p3.x) * (ox - p3.x) + (oy - p3.y) * (oy - p3.y));
		ret.x = ox;
		ret.y = oy;
		ret.r = (r1 + r2 + r3) / 3;
	} else {
		ret.r = -1;
	}
	return ret;
}
int getIntersectFromCircles(circle &c1, circle &c2, point &p1, point &p2) {
	double d = dist(c1.getCenter(), c2.getCenter());
	if (d > c1.r + c2.r)
		return -1;
	if (d < abs(c1.r - c2.r))
		return -1;
	double s = (c1.r + c2.r + d) / 2.0;
	double area = sqrt(s * (s - c1.r) * (s - c2.r) * (s - d));
	double h = 2 * area / d;
	point v = c2.getCenter() - c1.getCenter();
	v = v * (1.0 / abs(v));
	point m = c1.getCenter() + v * sqrt(c1.r * c1.r - h * h);
	point n = point(-v.y, v.x);
	p1 = m + n * h;
	p2 = m - n * h;
	return 0;
}
int N, M, K, T, Q, H, W;
struct niku {
	int x, y, c;
};
int check(vector< niku > &A, double t) {
	vector< circle > C(N);
	//t = 2.4;
	rep(i, N) {
		C[i] = circle(t / (double)A[i].c, (double)A[i].x, (double)A[i].y);
	}
	vector< point > E;
	rep(i, N) rep(j, N) if (i < j) {
		point p1, p2;
		int res = getIntersectFromCircles(C[i], C[j], p1, p2);
		if (res == 0) {
			E.push_back(p1);
			E.push_back(p2);
			// cout << i << " " << j << endl;
			// cout << p1.x << " " << p1.y << endl;
			// cout << p2.x << " " << p2.y << endl;
		}
	}
	rep(i, N) E.push_back(C[i].getCenter());
	// rep(i, N) cout << C[i].r << " " << C[i].x << " " << C[i].y << endl;
	//rep(i, E.size()) cout << E[i].x << " " << E[i].y << endl;
	int ret = 0;
	for (auto p : E) {
		int tmp = 0;
		rep(i, N) {
			if (dist(p, C[i].getCenter()) < C[i].r + EPS)
				tmp++;
		}
		chmax(ret, tmp);
	}
	return ret;
}
signed main() {
	cin >> N >> K;
	vector< niku > A(N);
	rep(i, N) cin >> A[i].x >> A[i].y >> A[i].c;
	double l = 0.0, r = 1e6;
	rep(_, 100) {
		double m = (l + r) * 0.5;
		if (check(A, m) >= K) {
			r = m;
		} else {
			l = m;
		}
	}
	cout << r << endl;

	// cout << "test" << endl;
	// circle c1(0.8, 0, 0), c2(1.2, 1, 0);
	// point p1, p2;
	// kouten(c1, c2, p1, p2);
	// cout << p1.x << " " << p1.y << endl;
	// cout << p2.x << " " << p2.y << endl;

	return 0;
}

Measured memory_bytes: 384