// Skyqwq
#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb push_back

typedef long long LL;
typedef pair<int, int> PII;

template <typename T> void inline read(T &x) {
	x = 0; int f = 1; char s = getchar();
	while (s < '0' || s > '9') { if (s == '-') { f = -1; } s = getchar(); }
	while (s >= '0' && s <= '9') x = x * 10 + (s ^ 48), s = getchar();
	x *= f;
}

template <typename T> bool inline chkMin(T &x, T y) { return y < x ? x = y, 1 : 0; }
template <typename T> bool inline chkMax(T &x, T y) { return y > x ? x = y, 1 : 0; }

int X, Y;

const double PI = acos(-1);

double u, o, Z, W;

double f(double x) {
	return Z * exp((x - u) * (x - u) * W);
}

double get(double l, double r) {
	double mid = (l + r) / 2;
	double vl = f(l), vmid = f(mid), vr = f(r);
	return (vl + vmid * 4 + vr) / 6 * (r - l);
}

const double eps = 1e-6;

double inline calc(double l, double r) {
//	cerr << l << " ???" << r << endl;
	double mid = (l + r) / 2;
	double w = get(l, r), o = get(l, mid) + get(mid, r);
	if (r - l < 1 && fabs(o - w) < eps) return w;
	return calc(l, mid) + calc(mid, r);
}

const int N = 16005;

double h[N];

void inline baoli() {
	h[0] = 1;
	int s = 0;
	for (int i = 1; i <= Y; i++) {
		for (int j = s; j >= 0; j--) {
			for (int k = 1; k < X; k++)
				h[j + k] += h[j] / X;
			h[j] /= X;
		}
		s += X - 1;
	}
	for (int i = 0; i < 10; i++) {
		int A, B;
		read(A), read(B);
		double ret = 0;
		for (int j = A; j <= B; j++) ret += h[j];
		printf("%.12lf\n", ret);
	}
	for (int i = 0; i <= s; i++) h[i] = 0;
}

int main() {
	int T; read(T);
	while (T--) {
		read(X), read(Y);
		if (Y <= 800) {
			baoli();
		} else {
			u = (X - 1.0) / 2 * Y, o = (X * X - 1) / 12.0 * Y;
			Z = 1 / sqrt(2 * PI * o);
			W = -1 / (2 * o);
			for (int i = 0; i < 10; i++) {
				int A, B;
				read(A), read(B);
				printf("%.12lf\n", calc(A, B));
			}
		}
	}	
	return 0;
}