calc.rb

require 'nokogiri'
require 'open-uri'

html = Nokogiri::HTML(File.open(File::expand_path('./source.txt')))

prices = html.css('#kagKinDisp').map {|price| price.content.delete(",").to_i }

times = html.css('#hesKaisuDisp').map(&:content)

result = Array.new

prices.zip(times).each do |price, time|
  price / 3 if time == "3"
  result << price
end

p result.inject(:+)