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

