Question

What is answer? and how can I solve it?

How many days must be picked from a 2018 calendar to ensure that at least 3 days fall in the same month?

1. 14

2. 25

3. 33

4. 37

Answer 1

Extremely unfavourable case is choosing 12 days and each of them belongs to different month that is none of two belongs to same month.Similarly for choosing 24 days extremely unfavourable case is each month contain 2 days of that 24 days.Now if we choose another day then one of the month must contain (2+1=3) days.Therefore we have to choose 25 days from a 2018 calendar to ensure that at least 3 days fall in the same month.

Required option is ""option 2. 25""