codeforce - Computer Game

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

int main()
{
    long long int q,n,k,a,b;
    cin>>q;
    while(q--)
    {
        long long ans,x,y,z;
        cin>>k>>n>>a>>b;
        if(k<=n*b)
        {
            ans=-1;
        }
        else
        {
            x=k-(n*b);
            y=(x-1)/(a-b);
            if(y>=0)
            {
                ans=min(n,y);
            }
            else ans=-1;
        }
        cout<<ans<<endl;
    }
    return 0;
}