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

int main(void){
    int i, N, M, P;

    while(1){
        scanf("%d %d %d", &N, &M, &P);
        if(N == 0){
            break;
        }

        int *X = (int *)malloc(N * sizeof(int));
        double sum = 0;

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

        if(X[M - 1] == 0){
            printf("0\n");
            continue;
        }
        else{
            sum -= sum * P / 100;
            printf("%d\n", (int)(sum / X[M - 1]));
        }
    }
    
    return 0;
}