#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "debug.hpp"
#else
#define debug(...) 1
#endif

void solve() {
    long double p;
    int k;
    cin >> p >> k;
    if (p == 0) {
        cout << k << '\n';
    } else {
        long double c = 1;
        for (int i = 0; i < k; i++) {
            c *= (1 - p);
        }
        long double ans = (1 - c) / p;
        cout << fixed << setprecision(15) << ans << '\n';
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
}