#include <stdio.h>

int main(void){
    int n,m,p,i,sum,map[100];
    for(;sum=0,scanf("%d %d %d",&n,&m,&p),n;){
        for(i=0;i<n;i++){
            scanf("%d",&map[i]);
            sum+=map[i];
        }
        sum*=(100-p);
        if(map[m-1] == 0)
            printf("0\n");
        else
            printf("%d\n",sum/map[m-1]);
    }
    return 0;
}