def main
  loop do
    n,m,p = gets.chomp.split.map(&:to_i)
    break if (n|m|p) == 0

    player = []
    sum = 0
    n.times do
      x = gets.chomp.to_i
      sum += x * 100
      player << x
    end
    prize = sum * (100 - p) / 100

    puts player[m-1] == 0 ? 0 : prize / player[m-1]
  end
end

main