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

// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
// #define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>

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

typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;

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(lld t) {cerr << t;}
void _print(double t) {cerr << t;}
void _print(ull t) {cerr << t;}

template <class T, class V> void _print(pair <T, V> p);
template <class T> void _print(vector <T> v);
template <class T> void _print(set <T> v);
template <class T, class V> void _print(map <T, V> v);
template <class T> void _print(multiset <T> v);

template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.first); cerr << ","; _print(p.second); cerr << "}";}
template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}

#define int long long
#define endl        "\n"
#define fast        ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
/*************************************************************************************************************************/ 

void solve() {
	int n, x, t;	
	cin >> n >> x >> t;

	int l = n - 1;
	int r = t / x;

	int ans;
	
	if(l < r) {
		ans = l;
	}	else {
		ans = r;
	}

	if(!ans) {
		cout << 0 << endl;
		return;
	}

	int right = ans * (ans - 1) / 2;

	int res = max(0LL , right) + ans * (n - ans);

	cout << res << endl;
}	


int32_t main() {
	fast;
#ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
	freopen("Error.txt", "w", stderr);
#endif

	int t;
	cin >> t;
	while(t--) {
		solve();
	}

	return 0;
}