Question:
A mint prepares metallic calendars specifying months, dates and days in the form of monthly sheets (one plate for each month). How many types of February calendars should it prepare to serve for all the possibilities in the future years?
Solution:
To find: types of February calendars that can be prepared.
There are two factors to develop FEBRUARY metallic calendars
(1) The day on the start of the year of which possibility $=7$
(2) Whether the year is leap year or not of which possibility is $=2$
So, number of FEBRUARY calendars possibilities to serve in future years $=7 \times 2=14$