#include<stdio.h>
#include<stdlib.h>

int main() {

	int N,M;
	double P;
	int *X;
	int sum;
	int i,a=0,Answer[1000];

	for(;;) {
		scanf("%d %d %lf",&N,&M,&P);
		if(N==0&&M==0&&P==0) break;

		X=(int *)malloc(N*sizeof(int));

		sum=0;
		for(i=0;i<N;i++) {
			scanf("%d",&X[i]);
			sum+=X[i]*100;
		}

		if(X[M-1]==0)
			Answer[a]=0;
		else
			Answer[a]=(sum*((100.0-P)/100.0))/X[M-1];
		a++;
	}

	for(i=0;i<a;i++)
		printf("%d\n",Answer[i]);

	return 0;
}