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

int main(){
	int t;
	cin >> t;
	cout << fixed << setprecision(11);
	while(t--){
		double p;
		int k;
		cin >> p >> k;
		if(p>0){
			//公比数列の和：1+(1-p)+(1-p)^2+...+(1-p)^(k-1)
			double r=1-p;
			cout << (1-pow(r,k))/p << endl;
		}else{
			cout << k << endl;
		}
	}
}