#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-10;
void File()
{freopen("D:\\in.txt","r",stdin);freopen("D:\\out.txt","w",stdout);
}
template <class T>
inline void read(T &x)
{char c = getchar();x = 0;while(!isdigit(c)) c = getchar();while(isdigit(c)){x = x * 10 + c - '0';c = getchar();}
}int T,n,m,y,x,d,len;
int L[500];
double p[500];
bool f[500];int const maxn = 500;
double a[maxn][maxn],ans[maxn];
bool free_x[maxn];int sgn(double x)
{return (x>eps)-(x<-eps);
}
int gauss()
{int i, j, k;int max_r;int col;double temp;int free_x_num;int free_index;int equ = len,var = len;col = 0;memset(free_x,true,sizeof(free_x));memset(ans,0,sizeof ans);for (k = 0; k < equ && col < var; k++, col++){max_r = k;for (i = k + 1; i < equ; i++){if (sgn(fabs(a[i][col]) - fabs(a[max_r][col]))>0) max_r = i;}if (max_r != k){for (j = k; j < var + 1; j++) swap(a[k][j], a[max_r][j]);}if (sgn(a[k][col]) == 0 ){k--; continue;}for (i = k + 1; i < equ; i++){if (sgn(a[i][col])!=0){double t = a[i][col] / a[k][col];for (j = col; j < var + 1; j++){a[i][j] = a[i][j] - a[k][j] * t;}}}}for(i=k;i<equ;i++)if(sgn(a[i][col])!=0) {return 0;}if (k < var){for (i = k - 1; i >= 0; i--){free_x_num = 0;for (j = 0; j < var; j++){if ( sgn(a[i][j])!=0 && free_x[j]){free_x_num++, free_index = j;}}if(free_x_num>1)    continue;temp = a[i][var];for (j = 0; j < var; j++){if (sgn(a[i][j])!=0 && j != free_index) temp -= a[i][j] * ans[j];}ans[free_index] = temp / a[i][free_index];free_x[free_index] = 0;}return var - k;}for (i = var - 1; i >= 0; i--){temp = a[i][var];for (j = i + 1; j < var; j++){if (sgn(a[i][j])!=0) temp -= a[i][j] * ans[j];}ans[i] = temp / a[i][i];}return 1;
}void bfs()
{memset(f,0,sizeof f);queue<int>q;q.push(x); f[x]=1;while(!q.empty()){int x = q.front(); q.pop();for(int i=1;i<=m;i++){if(p[i]<eps) continue;if(f[(x+i)%len]==0){f[(x+i)%len]=1;q.push((x+i)%len);}}}
}int main()
{scanf("%d",&T);while(T--){scanf("%d%d%d%d%d",&n,&m,&y,&x,&d);for(int i=1;i<=m;i++){int x; scanf("%d",&x);p[i]=1.0*x/100;if(p[i]<eps) p[i]=0;}for(int i=0;i<n;i++) L[i]=i; len=n;int tmp=n-2 ,pos = n; while(tmp>=1) L[pos++]=tmp--;len=pos;if(d==1){for(int i=n;i<=2*(n-1);i++) if(L[i]==x) { x=i; break; }}bfs();bool fail=1;for(int i=0;i<len;i++) if(L[i]==y&&f[i]==1) fail=0;if(fail==1){printf("Impossible !\n");continue;}memset(a,0,sizeof a);for(int i=0;i<len;i++){if(L[i]==y) continue;if(f[i]==0) continue;a[i][i]=-1;for(int j=1;j<=m;j++){if(L[(i+j)%len]==y) a[i][(i+j)%len]=0;else a[i][(i+j)%len]+=p[j];a[i][len]-=p[j]*j;}}gauss();printf("%.2f\n",ans[x]);}return 0;
}