while true
    n, m, p = gets.chomp.split.map(&:to_i)
    break if [n, m, p] == [0, 0, 0]
    arr = [0]
    n.times{arr << gets.to_i}
    sum = arr.inject(:+) * 100
    sum = sum * (100 - p) / 100
    puts (arr[m] == 0) ? 0 : sum / arr[m]
end
