#include <stdio.h>
int main(void)
{
  int i,n,m,p,ans;
  while(scanf("%d %d %d",&n,&m,&p)!=0&&n+m+p){
    int sum=0
    int x[n];
    for(i=0;i<n;i++){
      scanf("%d",x[i]);
      sum+=x[i];
    }
    sum*=100;
    sum*=1-(p/100);
    ans=sum/x[m];
    printf("%d\n",ans);
  }
  return 0;
}