#include<bits/stdc++.h>

#define ll long long
#define ld long double
#define pb push_back

using namespace std;

int l,s,t;
ld factor;
int solve(int v1, int v2, int knock){
    if(v2-v1<=t)return knock;
    int slt=(knock+1)*s;
    int pos=(int)((v2-v1)*factor+v1);
    pos=min(pos,v2-t);
    ll val=(ll)pos*(knock+1)*s;
    if(val>l)return -1;
    int r=solve(pos,v2,knock+1);
    if(r==-1)return -1;
    int l=solve(v1,pos,knock+1);
    if(l==-1)return -1;
    return max(l,r);
}


int main(){
    int o;
    scanf("%i",&o);
    while(o--){
        int v1,v2;
        scanf("%i %i %i %i %i",&l,&v1,&v2,&t,&s);
        ld l=0.5,r=1;
        int ans=-1;
        for(int i=0;i<100;i++){
            ld m=(l+r)/2;
            factor=m;
            int x=solve(v1,v2,0);
            if(x!=-1){
                r=m;
                ans=x;
            }
            else{
                l=m;
            }
        }
        if(ans==-1){
            printf("impossible\n");
        }
        else{
            printf("%i\n",ans);
        }
    }
}