A leap year has 366 days
366 days = 52 weeks + 2 days
That 2 days may be (Sun, Mon) , (Mon, Tue) , (Tue, Wed) , (Wed, Thu) , (Thu, Fri) (Fri, Sat) , (Sat, Sun)
Let E ⟶ event of getting 53 Sundays & 53 Mondays.
No. of favourable outcomes = 1 {(Sun, Mon)}
Since 52 weeks has 52 Sundays & 52 Mondays & the extra 2 days must be Sunday & Monday.
Total no. of possible outcomes = 7
P(E) = (No.of favorable outcomes)/(Total no.of possible outcomes) = 1/7