import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  try {
    for (; ; ) {
      const N = readInt;
      const M = readInt;
      auto A = new real[N];
      auto B = new real[N];
      auto P = new real[N];
      foreach (i; 0 .. N) {
        A[i] = 1.0L / readInt;
        B[i] = 1.0L / readInt;
        P[i] = 1.0L / readInt;
      }
      
      auto dp = new real[][](M + 1, 1 << N);
      dp[0][0] = 0.0L;
      foreach (i; 0 .. N) {
        foreach (p; 0 .. 1 << i) {
          dp[0][p | 1 << i] = dp[0][p] + A[i];
        }
      }
      foreach (m; 1 .. M + 1) {
        dp[m][] = dp[m - 1][];
        foreach (p; 0 .. 1 << N) {
          foreach (i; 0 .. N) if (p & 1 << i) {
            real score = 0.0L;
            score += P[i] * (B[i] + dp[m][p - (1 << i)]);
            score += (1.0L - P[i]) * dp[m - 1][p];
            chmax(dp[m][p], score);
          }
        }
      }
      writefln("%.12f", dp[M][$ - 1]);
    }
  } catch (EOFException e) {
  }
}