current

            <% @page = Page.last %>
            <% t = @page.hours.to_i * 60 + @page.minutes.to_i %>
            <% hour, t = t.divmod(60) %>
            <%= "%02d:%02d" % [hour, t] %>

current divmod

            <% @page = Page.last %>
            <% t = @page.hours.to_i * 60 + @page.minutes.to_i %>
            <% hour, t = t.divmod(60) %>
            <%= "%02d:%02d" % [hour, t] %>

sleepcalc time Time.new

midnight = Time.new.at_beginning_of_day # => 2017-04-12 00:00:00 +0300
time_sleep = midnight + 18.hours + 30.minutes # => 2017-04-12 18:30:00 +0300
time_wake_up = time_sleep + 8.hours # => 2017-04-13 02:30:00 +0300
time_wake_up.hour # => 2
time_wake_up.min # => 30