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

// macros
#define pb emplace_back
#define mk make_pair
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define irep(itr, st) for(auto itr = (st).begin(); itr != (st).end(); ++itr)
#define irrep(itr, st) for(auto itr = (st).rbegin(); itr != (st).rend(); ++itr)
#define whole(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define bit(n) (1LL<<(n))
// functions
template <typename T> void unique(T& c){c.erase(std::unique(c.begin(), c.end()), c.end());}
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}
template <typename T> ostream &operator<<(ostream &os, const vector<T>& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << "(" << p.first << ", " << p.second << ")"; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << "(" << itr->first << ", " << itr->second << ")"; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << "(" << itr->first << ", " << itr->second << ")"; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
//  types
using ll = long long int;
using P = pair<int, int>;
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-8;
const int mod = 1000000007;
const int dx[4] = {-1, 0, 1, 0};
const int dy[4] = {0, -1, 0, 1};
// io
struct fast_io{
  fast_io(){ios_base::sync_with_stdio(false); cin.tie(nullptr); cout << fixed << setprecision(20);}
} fast_io_;

using lod = long double;
lod x[100], y[100], c[100];

int main(int argc, char const* argv[])
{
  int n, k; cin >> n >> k;
  rep(i, n)cin >> x[i] >> y[i] >> c[i];
  lod ld = 0., rd = 400000.;
  rep(i_, 200){
    lod md = (ld + rd) / 2.;
    vector<lod> r(n);
    rep(i, n){
      r[i] = md / (lod)c[i];
    }
    vector<pair<lod, lod>> vp; vp.reserve(n * n);
    rep(i, n){
      FOR(j, i + 1, n){
        lod X = x[i], Y = y[i];
        lod X1 = x[j] - x[i], Y1 = y[j] - y[i];
        lod a = (X1 * X1 + Y1 * Y1 + r[i] * r[i] - r[j] * r[j]) / 2.;
        lod sq = (X1 * X1 + Y1 * Y1) * r[i] * r[i] - a * a;
        if(sq < EPS)continue;
        lod tx = X + (a * X1 + Y1 * sqrt(sq)) / (X1 * X1 + Y1 * Y1);
        lod ty = Y + (a * Y1 - X1 * sqrt(sq)) / (X1 * X1 + Y1 * Y1);
        vp.pb(tx, ty);
        tx = X + (a * X1 - Y1 * sqrt(sq)) / (X1 * X1 + Y1 * Y1);
        ty = Y + (a * Y1 + X1 * sqrt(sq)) / (X1 * X1 + Y1 * Y1);
        vp.pb(tx, ty);
      }
      vp.pb(x[i], y[i]);
    }
    bool ok = false;
    for(auto e: vp){
      int cnt = 0;
      rep(i, n){
        lod dis = hypot(e.first - x[i], e.second - y[i]);
        if(dis <= r[i] + EPS)cnt++;
      }
      if(cnt >= k)ok = true;
    }
    if(ok)rd = md;
    else ld = md;
  }
  cout << rd << endl;
  return 0;
}


Measured memory_bytes: 384