0312-2 機率問題

#include <iostream>
#include <cmath>
#include<iomanip>
using namespace std;

int main()
{
    int s;
    while(cin>>s)
    {
        while(s>0)
        {
            int n=0,i=0;
            double p=0;
            cin>>n>>p>>i;
            double q=1-p;
            double ans=pow(q,i-1)*p/(1-pow(q,n));
            cout<<setprecision(4)<<ans<<endl;

            s--;
        }
    }
    return 0;
}