#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
using namespace std;
typedef long long LL;

class TestBettingStrategy
{
public:
	map<int, double> memo;
	double winProbability(int initSum, int goalSum, int rounds, int prob) 
	{
		memo.clear();
		return rec(initSum, 1, rounds, goalSum, prob/100.0);
	}

	double rec(int cur, int bet, int rest, int goal, double pWin)
	{
		if( cur >= goal ) return 1.0;
		if( cur < bet )   return 0.0;
		if( rest == 0 )   return 0.0;

		int key = rest*2000*2000 + cur*2000 + bet;
		if( memo.count(key) )
			return memo[key];
		return memo[key]
			=    pWin *rec(cur+bet, 1, rest-1, goal, pWin)
			+ (1-pWin)*rec(cur-bet, bet*2, rest-1, goal, pWin);
	}

// BEGIN CUT HERE
	public:
	void run_test(int Case) { if ((Case == -1) || (Case == 0)) test_case_0(); if ((Case == -1) || (Case == 1)) test_case_1(); if ((Case == -1) || (Case == 2)) test_case_2(); if ((Case == -1) || (Case == 3)) test_case_3(); }
	private:
	template <typename T> string print_array(const vector<T> &V) { ostringstream os; os << "{ "; for (typename vector<T>::const_iterator iter = V.begin(); iter != V.end(); ++iter) os << '\"' << *iter << "\","; os << " }"; return os.str(); }
	void verify_case(int Case, const double &Expected, const double &Received) { cerr << "Test Case #" << Case << "..."; if (Expected == Received) cerr << "PASSED" << endl; else { cerr << "FAILED" << endl; cerr << "\tExpected: \"" << Expected << '\"' << endl; cerr << "\tReceived: \"" << Received << '\"' << endl; } }
	void test_case_0() { int Arg0 = 10; int Arg1 = 11; int Arg2 = 4; int Arg3 = 50; double Arg4 = 0.875; verify_case(0, Arg4, winProbability(Arg0, Arg1, Arg2, Arg3)); }
	void test_case_1() { int Arg0 = 10; int Arg1 = 20; int Arg2 = 20; int Arg3 = 50; double Arg4 = 0.3441343307495117; verify_case(1, Arg4, winProbability(Arg0, Arg1, Arg2, Arg3)); }
	void test_case_2() { int Arg0 = 10; int Arg1 = 20; int Arg2 = 10; int Arg3 = 90; double Arg4 = 0.34867844010000015; verify_case(2, Arg4, winProbability(Arg0, Arg1, Arg2, Arg3)); }
	void test_case_3() { int Arg0 = 24; int Arg1 = 38; int Arg2 = 24; int Arg3 = 60; double Arg4 = 0.5940784635646947; verify_case(3, Arg4, winProbability(Arg0, Arg1, Arg2, Arg3)); }

// END CUT HERE
};
// BEGIN CUT HERE 
int main() { TestBettingStrategy().run_test(-1); }
// END CUT HERE
