Problem
COM-B1-M12-P002 Set 1. Months
#2
★☆☆☆☆ Level 1 of 5
Prove that among \(13\) people, two were born in the same month.
There are \(12\) months.
There are \(12\) months and \(13\) people. By the pigeonhole principle, two people fall in the same month.
Very short existence proof.