Fixing get-some-time

subjects/get-some-time.en.md

@@ -4,4 +4,8 @@
 
 Create a function `firstDayWeek` that receives a week of the year
 (from 1 to 53) and a year (as a string), and returns the first day
-of that week, in the format: 'dd-mm-yyyy'.
+of that week, in the format: 'dd-mm-yyyy'. By beginning of the week
+we mean the monday of that week.
+
+If the first week is requested and it starts on the previous year
+of the presented one, it should return the first day of the year.