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

