#include "bits/stdc++.h"
using namespace std;
using ll = long long;
ll MOD = 1e9 + 7;

using Real = double;
using Point = complex< Real >;
const Real EPS = 1e-6, PI = acos(-1);

inline bool eq(Real a, Real b) { return fabs(b - a) < EPS; }

Point operator*(const Point &p, const Real &d) {
	return Point(real(p) * d, imag(p) * d);
}

istream &operator>>(istream &is, Point &p) {
	Real a, b;
	is >> a >> b;
	p = Point(a, b);
	return is;
}

ostream &operator<<(ostream &os, Point &p) {
	return os << fixed << setprecision(10) << p.real() << " " << p.imag();
}

// 点 p を反時計回りに theta 回転
Point rotate(Real theta, const Point &p) {
	return Point(cos(theta) * p.real() - sin(theta) * p.imag(), sin(theta) * p.real() + cos(theta) * p.imag());
}

Real radian_to_degree(Real r) {
	return (r * 180.0 / PI);
}

Real degree_to_radian(Real d) {
	return (d * PI / 180.0);
}

// a-b-c の角度のうち小さい方を返す
Real get_angle(const Point &a, const Point &b, const Point &c) {
	const Point v(b - a), w(c - b);
	Real alpha = atan2(v.imag(), v.real()), beta = atan2(w.imag(), w.real());
	if (alpha > beta) swap(alpha, beta);
	Real theta = (beta - alpha);
	return min(theta, 2 * acos(-1) - theta);
}

namespace std {
	bool operator<(const Point &a, const Point &b) {
		return a.real() != b.real() ? a.real() < b.real() : a.imag() < b.imag();
	}
}


struct Line {
	Point a, b;

	Line() = default;

	Line(Point a, Point b) : a(a), b(b) {}

	Line(Real A, Real B, Real C) // Ax + By = C
	{
		if (eq(A, 0)) a = Point(0, C / B), b = Point(1, C / B);
		else if (eq(B, 0)) b = Point(C / A, 0), b = Point(C / A, 1);
		else a = Point(0, C / B), b = Point(C / A, 0);
	}

	friend ostream &operator<<(ostream &os, Line &p) {
		return os << p.a << " to " << p.b;
	}

	friend istream &operator>>(istream &is, Line &a) {
		return is >> a.a >> a.b;
	}
};

struct Segment : Line {
	Segment() = default;

	Segment(Point a, Point b) : Line(a, b) {}
};

struct Circle {
	Point p;
	Real r;

	Circle() = default;

	Circle(Point p, Real r) : p(p), r(r) {}
};

using Points = vector< Point >;
using Polygon = vector< Point >;
using Segments = vector< Segment >;
using Lines = vector< Line >;
using Circles = vector< Circle >;

Real cross(const Point &a, const Point &b) {
	return real(a) * imag(b) - imag(a) * real(b);
}

Real dot(const Point &a, const Point &b) {
	return real(a) * real(b) + imag(a) * imag(b);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_C
// 点の回転方向
int ccw(const Point &a, Point b, Point c) {
	b = b - a, c = c - a;
	if (cross(b, c) > EPS) return +1;  // "COUNTER_CLOCKWISE"
	if (cross(b, c) < -EPS) return -1; // "CLOCKWISE"
	if (dot(b, c) < 0) return +2;      // "ONLINE_BACK"
	if (norm(b) < norm(c)) return -2;  // "ONLINE_FRONT"
	return 0;                         // "ON_SEGMENT"
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_A
// 平行判定
bool parallel(const Line &a, const Line &b) {
	return eq(cross(a.b - a.a, b.b - b.a), 0.0);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_A
// 垂直判定
bool orthogonal(const Line &a, const Line &b) {
	return eq(dot(a.a - a.b, b.a - b.b), 0.0);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_A
// 射影
// 直線 l に p から垂線を引いた交点を求める
Point projection(const Line &l, const Point &p) {
	double t = dot(p - l.a, l.a - l.b) / norm(l.a - l.b);
	return l.a + (l.a - l.b) * t;
}

Point projection(const Segment &l, const Point &p) {
	double t = dot(p - l.a, l.a - l.b) / norm(l.a - l.b);
	return l.a + (l.a - l.b) * t;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_B
// 反射
// 直線 l を対称軸として点 p  と線対称にある点を求める
Point reflection(const Line &l, const Point &p) {
	return p + (projection(l, p) - p) * 2.0;
}

bool intersect(const Line &l, const Point &p) {
	return abs(ccw(l.a, l.b, p)) != 1;
}

bool intersect(const Line &l, const Line &m) {
	return abs(cross(l.b - l.a, m.b - m.a)) > EPS || abs(cross(l.b - l.a, m.b - l.a)) < EPS;
}

bool intersect(const Segment &s, const Point &p) {
	return ccw(s.a, s.b, p) == 0;
}

bool intersect(const Line &l, const Segment &s) {
	return cross(l.b - l.a, s.a - l.a) * cross(l.b - l.a, s.b - l.a) < EPS;
}

Real distance(const Line &l, const Point &p);

bool intersect(const Circle &c, const Line &l) {
	return distance(l, c.p) <= c.r + EPS;
}

bool intersect(const Circle &c, const Point &p) {
	return abs(abs(p - c.p) - c.r) < EPS;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_B
bool intersect(const Segment &s, const Segment &t) {
	return ccw(s.a, s.b, t.a) * ccw(s.a, s.b, t.b) <= 0 && ccw(t.a, t.b, s.a) * ccw(t.a, t.b, s.b) <= 0;
}

int intersect(const Circle &c, const Segment &l) {
	if (norm(projection(l, c.p) - c.p) - c.r * c.r > EPS) return 0;
	auto d1 = abs(c.p - l.a), d2 = abs(c.p - l.b);
	if (d1 < c.r + EPS && d2 < c.r + EPS) return 0;
	if (d1 < c.r - EPS && d2 > c.r + EPS || d1 > c.r + EPS && d2 < c.r - EPS) return 1;
	const Point h = projection(l, c.p);
	if (dot(l.a - h, l.b - h) < 0) return 2;
	return 0;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_7_A&lang=jp
int intersect(Circle c1, Circle c2) {
	if (c1.r < c2.r) swap(c1, c2);
	Real d = abs(c1.p - c2.p);
	if (c1.r + c2.r < d) return 4;
	if (eq(c1.r + c2.r, d)) return 3;
	if (c1.r - c2.r < d) return 2;
	if (eq(c1.r - c2.r, d)) return 1;
	return 0;
}

Real distance(const Point &a, const Point &b) {
	return abs(a - b);
}

Real distance(const Line &l, const Point &p) {
	return abs(p - projection(l, p));
}

Real distance(const Line &l, const Line &m) {
	return intersect(l, m) ? 0 : distance(l, m.a);
}

Real distance(const Segment &s, const Point &p) {
	Point r = projection(s, p);
	if (intersect(s, r)) return abs(r - p);
	return min(abs(s.a - p), abs(s.b - p));
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_D
Real distance(const Segment &a, const Segment &b) {
	if (intersect(a, b)) return 0;
	return min({ distance(a, b.a), distance(a, b.b), distance(b, a.a), distance(b, a.b) });
}

Real distance(const Line &l, const Segment &s) {
	if (intersect(l, s)) return 0;
	return min(distance(l, s.a), distance(l, s.b));
}

Point crosspoint(const Line &l, const Line &m) {
	Real A = cross(l.b - l.a, m.b - m.a);
	Real B = cross(l.b - l.a, l.b - m.a);
	if (eq(abs(A), 0.0) && eq(abs(B), 0.0)) return m.a;
	return m.a + (m.b - m.a) * B / A;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_C
Point crosspoint(const Segment &l, const Segment &m) {
	return crosspoint(Line(l), Line(m));
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_7_D
pair< Point, Point > crosspoint(const Circle &c, const Line l) {
	Point pr = projection(l, c.p);
	Point e = (l.b - l.a) / abs(l.b - l.a);
	if (eq(distance(l, c.p), c.r)) return { pr, pr };
	double base = sqrt(c.r * c.r - norm(pr - c.p));
	return { pr - e * base, pr + e * base };
}

pair< Point, Point > crosspoint(const Circle &c, const Segment &l) {
	Line aa = Line(l.a, l.b);
	if (intersect(c, l) == 2) return crosspoint(c, aa);
	auto ret = crosspoint(c, aa);
	if (dot(l.a - ret.first, l.b - ret.first) < 0) ret.second = ret.first;
	else ret.first = ret.second;
	return ret;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_7_E
pair< Point, Point > crosspoint(const Circle &c1, const Circle &c2) {
	Real d = abs(c1.p - c2.p);
	Real a = acos((c1.r * c1.r + d * d - c2.r * c2.r) / (2 * c1.r * d));
	Real t = atan2(c2.p.imag() - c1.p.imag(), c2.p.real() - c1.p.real());
	Point p1 = c1.p + Point(cos(t + a) * c1.r, sin(t + a) * c1.r);
	Point p2 = c1.p + Point(cos(t - a) * c1.r, sin(t - a) * c1.r);
	return { p1, p2 };
}

int main() {
	int N, K;
	cin >> N >> K;
	if (K == 1) {
		cout << 0 << endl;
		return 0;
	}
	vector<int> x(N);
	vector<int> y(N);
	vector<int> c(N);
	for (int i = 0; i < N; i++) {
		cin >> x[i] >> y[i] >> c[i];
	}
	double l = 0, r = 1e9;
	for (int T = 0; T < 100; T++) {
		double mid = (l + r) / 2;
		vector<Circle> cs;
		for (int i = 0; i < N; i++) {
			cs.emplace_back(Point(x[i], y[i]), mid / c[i]);
		}
		vector<Point> ps;
		for (int i = 0; i < N; i++) {
			ps.push_back(cs[i].p);
			for (int j = i + 1; j < N; j++) {
				if (intersect(cs[i], cs[j])) {
					auto ret = crosspoint(cs[i], cs[j]);
					ps.push_back(ret.first);
					ps.push_back(ret.second);
				}
			}
		}
		bool ok = 0;
		for (auto p : ps) {
			int cnt = 0;
			for (int i = 0; i < N; i++) {
				double d = distance(cs[i].p, p);
				if (d <= cs[i].r + EPS) cnt++;
			}
			if (cnt >= K) {
				ok = 1;
				break;
			}
		}
		if (ok) r = mid;
		else l = mid;
	}
	printf("%.15lf\n", l);
}

Measured memory_bytes: 428