The probability that an year chosen at random has 53 Sundays is :

Explanation

A normal year has 52 Sundays, 52 Mondays, 52 Tuesday, 52 Wednesday, 52 Thursday, 52 Fridays,
52 Saturdays, +1 day that could be anything depending upon the year consideration.

For a leap year to have 35 Sundays, it should start from Saturday or Sunday.

So, basically we have to find the probability that year start from Saturday or Sunday (P)


`P=frac{text { first day to be Saturday or Sunday }}{{ T otal no. of days in a week }}`



...