#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <queue>
#include <algorithm>
#include <math.h>
using namespace std;
#define M 205
#define eps 1e-8
int equ, var;
double a[M][M], x[M];int Gauss ()
{int i, j, k, col, max_r;for (k = 0, col = 0; k < equ && col < var; k++, col++){max_r = k;for (i = k+1; i < equ; i++)if (fabs (a[i][col]) > fabs (a[max_r][col]))max_r = i;if (k != max_r){for (j = col; j < var; j++)swap (a[k][j], a[max_r][j]);swap (x[k], x[max_r]);}x[k] /= a[k][col];for (j = col+1; j < var; j++) a[k][j] /= a[k][col];a[k][col] = 1;for (i = 0; i < equ; i++) if (i != k){x[i] -= x[k] * a[i][k];for (j = col+1; j < var; j++) a[i][j] -= a[k][j] * a[i][col];a[i][col] = 0;}}return 1;
}//has[x]表示人在x点时的变量号，因为我们只用可达状态建立方程，所以需要编号
int has[M], vis[M], k, e, n, m;
double p[M], sum;int bfs (int u)
{memset (has, -1, sizeof(has));memset (a, 0, sizeof(a));            //忘记初始化WA勒，以后得注意memset (vis, 0, sizeof(vis));int v, i, flg = 0;queue<int> q;q.push (u);k = 0;has[u] = k++;while (!q.empty ()){u = q.front ();q.pop ();if (vis[u]) continue;vis[u] = 1;if (u == e || u == n-e)       //终点有两个，你懂的~{a[has[u]][has[u]] = 1;x[has[u]] = 0;flg = 1;continue;}//E[x] = sum ((E[x+i]+i) * p[i])// ----> E[x] - sum(p[i]*E[x+i]) = sum(i*p[i])a[has[u]][has[u]] = 1;x[has[u]] = sum;for (i = 1; i <= m; i++){//非常重要！概率为0，该状态可能无法到达，如果还去访问并建立方程会导致无解if (fabs (p[i]) < eps) continue;v = (u + i) % n;if (has[v] == -1) has[v] = k++;a[has[u]][has[v]] -= p[i];q.push (v);}}return flg;
}int main()
{int t, s, d, i;scanf ("%d", &t);while (t--){scanf ("%d%d%d%d%d", &n, &m, &e, &s, &d);n = 2*(n-1);sum = 0;for (i = 1; i <= m; i++){scanf ("%lf", p+i);p[i] = p[i] / 100;sum += p[i] * i;}if (s == e){puts ("0.00");continue;}//一开始向左，起点要变if (d > 0) s = (n - s) % n;if (!bfs (s)){puts ("Impossible !");continue;}equ = var = k;Gauss ();printf ("%.2f\n", x[has[s]]);}return 0;
}