#include <bits/stdc++.h>

using namespace std;

int main() {
	int T;
	cin >> T;
	while (T--) {
		int a, v;
		cin >> a >> v;
		double ans = 2 / 3.0 * a / (double) v;
		printf("%.16lf\n", ans);
	}

	return 0;
}