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

int main() {
	int T;
	cin >> T;
	for( int i = 0; i < T; i++ ) {
		double p;
		int K;
		cin >> p >> K;
		double ans = 0, r = 1 - p, a = 1;
		for( int i = 0; i < K; i++ ) {
			ans += a;
			a *= r;
		}
		cout << fixed << setprecision(12) << ans << endl;
	}
}