Question

What is the probability that a leap year has 53 sundays ?

Answer 1

A leap year has 366 days, and, therefore, 52 weeks and 2 days. These 2 days may be

(i) Sunday and Monday or (ii) Monday and Tuesday

or (iii) Tuesday and Wednesday or (iv) Wednesday and Thursday

or (v) Thursday and Friday or (vi) Friday and Saturday

or (vii) Saturday and Sunday.

Thus, out of 7 possibilities, 2 favour the event that one of the two days is a Sunday

$\therefore$ required probability $=\frac{2}{7}$