#include<bits/stdc++.h>
#define ll long long
#define si set<int>
#define sll set<ll>
#define sc set<char>
#define lcm(a,b) a*b/__gcd(a,b)
#define siitr set<int>::iterator
#define scit set<char>::iterator
#define mp make_pair
#define mapint map<int, int >
#define vi vector<int>
#define vs vector<string>
#define vll vector<long long>
#define vc vector<char>
#define vb vector<bool>
#define vd vector<double>
#define vviitr vector<vector<int> >::iterator
#define vvi vector<vector<int> >
#define vvc vector< vector<char> >
#define vvb vector<vector<bool> >
#define viitr vector<int>::iterator
#define vcitr vector<char>::iterator
#define f(i,j,n,k) for(int i=j;i<=n;i+=k)
#define all(c) c.begin(),c.end()
#define allr(c) c.rbegin(),c.rend()
#define pb push_back
#define pi pair<ll int,ll int>
#define MOD 1000000007
#define hell 1000000007

ll int  gcdfun(ll int x, ll int y){ if(y==0) return x; else return gcdfun(y,x%y); }
using namespace std;
ll int lcmfun(ll int x,ll int y){
     return x*y/gcdfun(x,y);
}
ll int power(ll int x,ll int y)
{
    if (y == 0)
        return 1;
    else if (y % 2 == 0)
        return ((power(x, y / 2)%hell ) * ( power(x, y / 2) )%hell)%hell;
    else
        return ((x %hell) * ((power(x, y / 2))%hell) * ((power(x, y / 2) )%hell));
}
 
ll minf(ll a,ll b){if(a<b) return a; else return b;}
ll maxf(ll a,ll b){if(a<b) return b; else return a;}

ll int fact(ll int n,ll int p)
{
    if (n >= p)
        return 0;
 
   ll int result = 1;
    for (ll int i = 1; i <= n; i++)
        result = (result * i) % p;
 
    return result;
}

ll int nCr(ll int n, ll int r,ll int p)
{
    if (r > n - r)
        r = n - r;
 
    ll int C[r + 1];
    memset(C, 0, sizeof(C));
 
    C[0] = 1;
 
    for (ll int i = 1; i <= n; i++) {
        for (ll int j = minf(i, r); j > 0; j--)
            C[j] = (C[j] + C[j - 1]) % p;
    }
    return C[r];
}
 
using namespace std;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
    
    ll t;cin>>t;
    while(t--)
    {
        ll n,x,k;
        cin>>n>>x>>k;
        if(x>k)cout<<0<<endl;
        else
        {
            ll ans;
            ll p=k/x;
            if(n-p-1>0)
             ans=p*(n-p-1)+p*(p+1)/2;
            else
            {
               // cout<<"k";
                p=p+(n-p-1);
                ans=(p*(p+1))/2;
            }
            cout<<ans<<endl;
        }
        
    }
        
    
}

