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

#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define endl "\n"
#define PI 3.141592653589793238462
#define pb push_back()
typedef long long ll;
const ll MOD = 1e9 + 7;

#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#else
#define debug(x)
#endif

void _print(ll t) {cerr << t;}
void _print(int t) {cerr << t;}
void _print(string t) {cerr << t;}
void _print(char t) {cerr << t;}
void _print(double t) {cerr << t;}


template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}



void solve()
{
	ll n, x, t;
	cin>>n>>x>>t;
	if (x>t)
	{
		cout<<"0"<<endl;
		return;
	}
	ll temp = t/x;
	if (temp >= n-1)
	{
		ll ans = n-1;
		ans = ans * (ans + 1)/2;
		cout<<ans<<endl;
	}
	else
	{
		ll ans1 = temp;
		ans1 = ans1 * (ans1 + 1)/2;
		ll ans2 = (n-1- temp)*temp;
		cout<<ans1 + ans2<<endl;
	}
}

int main()
{
#ifndef ONLINE_JUDGE
	freopen("Error.txt", "w", stderr);
#endif
	IOS;
	int k;
	cin >> k;
	while (k--)
	{
		solve();
	}
	return 0;
}