#include <iostream> 
#include <string> 
#include <set> 
#include <map> 
#include <stack> 
#include <queue> 
#include <vector> 
#include <utility> 
#include <iomanip> 
#include <sstream> 
#include <bitset> 
#include <cstdlib> 
#include <iterator> 
#include <algorithm> 
#include <cstdio> 
#include <cctype> 
#include <cmath> 
#include <math.h> 
#include <ctime> 
#include <cstring> 
#include <unordered_set> 
#include <unordered_map> 
using namespace std;

#define sync {ios_base ::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);}
#define rep(n) for(int i = 0;i<n;i++)
#define rep1(a,b) for(int i = a;i<b;i++)
#define int long long int
#define mod 1000000007

int n,x,t;

void solve()
{
    cin>>n>>x>>t;
    int ans = 0;
    if(t<x)
        ans = 0;
    else if(t==x)
        ans = n-1;
    else
    {
        int y = t/x;
        if(y>=n-1)
        {
            ans = n*(n-1)/2;
        }
        else
        {
            ans = y*(y+1)/2;
            ans += y*(n-1-y);
        }
        
    }

    cout<<ans;
    
}

int32_t main()
{

    #ifndef ONLINE_JUDGE
        freopen("input.txt","r",stdin);
        freopen("output.txt","w",stdout);
    #endif
    
    sync;
    int t = 1;
    cin>>t;
    while(t--){
        solve();
        cout<<"\n";
    }
    return 0;
}