#include<stdio.h>
int main(){
  int N,M,x[1001],i,sum,ans;
  double P;
  while(1){
    sum=0;
    ans=0;
    scanf("%d%d%lf",&N,&M,&P);
    if(N==0&&M==0&&P==0)break;
    P=(100-P)*0.01;
    for(i=0;i<N;i++){
      scanf("%d",&x[i]);
      sum=sum+x[i];
    }
    sum=sum*100;

    if(x[M-1]==0)printf("0\n");
    else{  ans=(sum*P)/x[M-1];
    printf("%d\n",ans);
    }
  }
  return 0;
}