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