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

int main(void) {
    int t;
    cin >> t;
    while(t--){
        double p;
        int k;
        cin >> p >> k;
        double ans=1;
        double prob=1-p;
        for(int i=1;i<k;++i){
            ans+=prob;
            prob*=1-p;
        }
        cout << fixed << setprecision(15) << ans << endl;
    }
    return 0;
}