#include <stdio.h>

int main() {
  int play;
  int i = 0;
  int win;
  int perc;
  int b;
  int wb;
  int betg = 0;

  while(1) {
    scanf("%d%d%d", &play, &win, &perc);
    if(play == 0 && win == 0 && perc == 0) break;
    betg = 0;
    for(i = 0; i < play; ++i) {
      scanf("%d", &b);
      betg += (b * 100);
      if(win == (i + 1)) {
        wb = b;
      }
    }
    (wb == 0) ? printf("%d\n", 0) : printf("%d\n", (int)(((float)betg * ((float)(100 - perc) * 0.01)) / wb));
  }
  return 0;
}