Question

What is the chance that a leap year, selected at random, will contain 53 Sundays?

Answer 1

A leap year consists of 366 days. It has 52 complete weeks and two more days. 

These two days can be {(Sun, Mon), (Mon, Tue), (Tue, Wed), (Wed, Thur), (Thur, Fri), (Fri, Sat), (Sat, Sun)}. 

∴ n(S) = 7 

Let event E : There are 53 Sundays. 

∴ E = {(Sun, Mon), (Sat, Sun)}

∴ n(E) = 2

∴ P(E) = \(\frac {n(E)}{n(S)} = \frac2 7\)