#include <stdio.h>
int b[1001]; double p[1001], f[1001][10][7], g[1001][10];
int main()
{
    int n, h, s, t1, t2; scanf("%d%d%d", &n, &h, &s);
    for (int i(1); i <= n; ++i) scanf("%lf", &p[i]), p[i] /= 100;
    int m; scanf("%d", &m); while (m--) { int i; scanf("%d", &i); b[i] = true; }
    scanf("%d%d", &t1, &t2);
    if (t1 >= t2 || !s)
    {
        for (int i(n); i; --i)
        {
            g[i][2] = (t2 + 1) / p[i] + g[i + 1][2] - t2;
            for (int j(3); j <= h; ++j)
                g[i][j] = p[i] * g[i + 1][j] + (1 - p[i]) * g[i][j - 1] + 1;
        }
        printf("%.6f\n", g[1][h]);
    }
    else
    {
        for (int i(n); i; --i)
            if (b[i])
            {
                double d[h + 1], e[h + 1]; for (int j(2); j <= h; ++j) d[j] = 1e9;
                for (int c(2); c <= h; ++c)
                {
                    e[c] = (t1 + 1) / p[i] + f[i + 1][c][s] - t1;
                    for (int j(c + 1); j <= h; ++j) e[j] = p[i] * f[i + 1][j][s] + (1 - p[i]) * e[j - 1] + 1;
                    for (int j(2); j < c; ++j) e[j] = e[c] + (c - j) * t1;
                    for (int j(2); j <= h; ++j) if (e[j] < d[j]) d[j] = e[j];
                }
                for (int j(2); j <= h; ++j) for (int k(0); k <= s; ++k) f[i][j][k] = d[j];
            }
            else
            {
                f[i][2][0] = (t2 + 1) / p[i] + f[i + 1][2][0] - t2;
                for (int k(0); k <= s; ++k) f[i][2][k] = p[i] * f[i + 1][2][k] + (1 - p[i]) * (f[i][2][k - 1] + t1) + 1;
                for (int j(2); j <= h; ++j) for (int k(0); k <= s; ++k)
                    f[i][j][k] = p[i] * f[i + 1][j][k] + (1 - p[i]) * f[i][j - 1][k];
            }
        printf("%.6f\n", f[1][h][s]);
    }
    return 0;
}