#include <bits/stdc++.h>
using namespace std;

#define int long long
#define double long double
#define rep(i, n) for (int i = 0; i < (n); i++)
#define reps(i, n) for (int i = 1; i <= (n); i++)
#define all(x) begin(x), end(x)
#define uniq(x) (x).erase(unique(all(x)), end(x))
#define bit(n) (1LL << (n))
#define dump(x) cerr << #x " = " << (x) << endl
using vint = vector<int>;
using vvint = vector<vint>;
using pint = pair<int, int>;
using vpint = vector<pint>;
template<typename T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
constexpr double pi = 3.1415926535897932384626433832795028L;
constexpr int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
constexpr int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int gcd(int a, int b) {
    while (b) { swap(a %= b, b); }
    return a;
}
int lcm(int a, int b) { return a / gcd(a, b) * b; }
template<typename T> void fin(T mes) {
    cout << mes << endl;
    exit(0);
}
template<typename T, typename U> bool chmax(T &a, const U &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template<typename T, typename U> bool chmin(T &a, const U &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}
template<typename T, typename U> ostream &operator<<(ostream &os, const pair<T, U> &rhs) {
    os << "(" << rhs.first << ", " << rhs.second << ")";
    return os;
}
template<typename T> ostream &operator<<(ostream &os, const vector<T> &rhs) {
    os << "{";
    for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
        os << *itr << (next(itr) != rhs.end() ? ", " : "");
    }
    os << "}";
    return os;
}
struct setup {
    static constexpr int PREC = 20;
    setup() {
        cout << fixed << setprecision(PREC);
        cerr << fixed << setprecision(PREC);
    };
} setup;

template<typename F> double bs(double ok, double ng, const F &check) {
    rep(i, 100) {
        double mid = (ok + ng) / 2;
        (check(mid) ? ok : ng) = mid;
    }
    return ok;
}

double dist(pair<double, double> p1, pair<double, double> p2) {
    return sqrt((p1.first - p2.first) * (p1.first - p2.first) + (p1.second - p2.second) * (p1.second - p2.second));
}

int N, K;
double x[110], y[110], c[110];
signed main() {
    double eps = 1e-8;
    cin >> N >> K;
    rep(i, N) { cin >> x[i] >> y[i] >> c[i]; }
    cout << bs(1000000, 0, [&](double t) {
        vector<pair<double, double>> ps;
        rep(i, N) {
            ps.push_back({x[i], y[i]});
        }
        rep(i, N) {
            rep(j, i) {
                double ri = t / c[i], rj = t / c[j];
                double x1 = x[j] - x[i];
                double y1 = y[j] - y[i];
                double a = (x1 * x1 + y1 * y1 + ri * ri - rj * rj) / 2;
                if ((x1 * x1 + y1 * y1) * ri * ri > a * a) {
                    ps.push_back({(a * x1 + y1 * sqrt((x1 * x1 + y1 * y1) * ri * ri - a * a)) / (x1 * x1 + y1 * y1)
                                      + x[i],
                                  (a * y1 - x1 * sqrt((x1 * x1 + y1 * y1) * ri * ri - a * a)) / (x1 * x1 + y1 * y1)
                                      + y[i]});

                    ps.push_back({(a * x1 - y1 * sqrt((x1 * x1 + y1 * y1) * ri * ri - a * a)) / (x1 * x1 + y1 * y1)
                                      + x[i],
                                  (a * y1 + x1 * sqrt((x1 * x1 + y1 * y1) * ri * ri - a * a)) / (x1 * x1 + y1 * y1)
                                      + y[i]});
                }
            }
        }
        int m = 0;
        rep(i, ps.size()) {
            int cur = 0;
            rep(j, N) {
                if (dist(ps[i], {x[j], y[j]}) < t / c[j] + eps) { cur++; }
            }
            chmax(m, cur);
        }
        return m >= K;
    }) << endl;
}

Measured memory_bytes: 512