Many people would think Friday the 13th will be an unlucky day. Is it possible
that there is no Friday on 13th through the whole year? How many Fridays at 13th
can we have in a year at most? Can you calculate it out?
Answer:
We can calculate out how many days there will be for the
13th on each month if we count from the beginning of the year (January 1). Then
we divide total days by 7 to get the remainders. We also need to consider the
leap year. Through the whole year we had all kinds of remainders, from 0 to 6.
The minimum of occurence for all the unique remainders was 1. It means that we
have at least one Friday on 13th. In a regular year, the best chance you can get
3 Fridays on 13th, which are in February, March and December because the
remainders of these 3 months are 2. In a leap year, the best chance you also can
get 3 Fridays on 13th, which are in January, April and July because the
remainders of these 3 months are 6.
No comments:
Post a Comment