CHFING.cpp

#include <bits/stdc++.h>
using namespace std;
long long t,n,k,d,last,first,N,ans;

typedef long long int ll; 

ll mulmod(ll a, ll b) 
{ 
    ll mod=1000000007;
    ll res = 0; 
    
        
    while (b > 0) 
    {
        if (b % 2 == 1)
            res = (res + a);
        
        res%=mod;
        a = (a * 2);
        a%=mod;
        b /= 2; 
  
    } 
    res%=mod;
    return res; 
} 

int main()
{
    int t;
    cin>>t;
    while(t--){
        
        cin>>n>>k;
        
        d=n-1;
        last=k-1;
        first=last%d;
        N=(last-first)/d + 1;
        ll z=last+first;
        
        if(N%2==0){
            N/=2;
        }else{
            z/=2;
        }        
        ans= mulmod(N,(z));
        //ans+=(first+last);
        //ans%=1000000007;

        cout<<ans%1000000007<<endl;
    }
    return 0;
}