get_week_days.rb

def get_days(date)
  last_day = date.end_of_month.day
  first_wday = date.wday
  total_days = [6, 7].include?(first_wday) ? 0 : 1
  (1..(last_day - 1)).reduce(total_days) do |result, _element|
    wday = ((first_wday + 1) > 7) ? first_wday % 7 + 1 : first_wday + 1
    first_wday += 1
    result += 1 unless [6, 7].include?(wday)
    result
  end
end