Question:
What is the probability that an ordinary year has 53 Mondays?
Solution:
An ordinary year has 365 days consisting of 52 weeks and 1 day.
This day can be any day of the week.
$\therefore \mathrm{P}$ (of this day to be Monday) $=\frac{1}{7}$
Thus, the probability that an ordinary year has 53 Mondays is $\frac{1}{7}$.