#include <stdio.h>

int main(){
	while(1){
		int n, m, p;
		int i, x;
		int sum = 0, win = 0;
		scanf("%d%d%d", &n, &m, &p);
		if(n == 0)
			break;
		m--;
		for(i=0; i<n; i++){
			scanf("%d", &x);
			sum += x;
			if(i == m)
				win = x;
		}
		sum *= 100;
		if(win == 0)
			puts("0");
		else
			printf("%d\n", sum * (100-p) / 100 / win);
	}
	return 0;
}