A leap year has 366 days, so on dividing it by 7, we get 52 weeks and 2 days more. 52 . weeks means 52 Sundays surely. Now, what will you say.
Perhaps you will say that probability of getting 52 Sundays in a leap year is 1. Your answer is not correct. Why?
Think about the two remaining days. If from the remaining 2 days, 1 day is the Sunday, then there are 53 Sundays in a leap year. So, question is not ended at the stage that probability is 1. We have to consider necessarily the two remaining days. The remaining 2 days may be (Sunday, Monday), (Monday, Tuesday), (Tuesday, Wednesday), (Wednesday, Thursday), (Thursday, Friday), (Friday, Saturday), (Saturday, Sunday).
For only 52 Sundays we want that the combination of (Sunday, Monday) or (Saturday, Sunday) do not occur. So, to get the required probability.
= (52 Sundays with probability 1) and (5 other possibilities out of 7 with probability `(5)/(7)`)
`=1xx(5)/(7)=(5)/(7)`
