test.rb

class Fixnum
  def is_palindrome?
    self.to_s.reverse == self.to_s
  end
end

count = 0
File.readlines('seed.txt').each do |line|
  start, finish = line.split(/\s/)
  count = (start.to_i..finish.to_i).to_a.map(&:to_i).reduce(0) do |s, n|
    s += n if n.is_palindrome?
  end
end

puts count