#include<stdio.h>
double cal(int n, int m, int k)
{
	if (k <= 0)
		return 1;
	double res = 0;
	res += (n - 1) / (double)n * cal(n - 1, m, k - m);
	res += 1 / (double)n * (m - 1) / m * cal(1, m - 1, k - (n - 1) * m - 1);
	return res;
}
void solve()
{
	int n, m, k;
	scanf("%d %d %d", &n, &m, &k);
	printf("%.20lf\n", cal(n, m, k));
	return;
}
int main()
{
	int t;
	scanf("%d", &t);
	for (; t > 0; t--)
		solve();
	return 0;
}