mythematics
  • Home
  • About
  • Contact

Challenge #15

Pizza Party!

Suppose there are 25 people at a party. We can always find at least one pair of people who have their birthdays in the same month. Explain why.

Suppose 25 people together consume a total of 250 slices of pizza. We can always find at least one pair of people who ate exactly the same number of slices. Explain why.

Follow-up Challenges

Is this statement true or false? Explain why. At party of 25 people, we can always find a group of three whose birthdays are in the same month.

Consider this statement: If 25 people consume a total of P slices of pizza, then we can find a group of three people who ate exactly the same number of slices. What is the smallest value of P for which this statement is always true?

Response Videos

Reach out to share your solution and we'll include it here! :)
Except where otherwise noted, content on this site is by Jason Ermer and licensed under
​a Creative Commons Attribution-Noncommercial 4.0 International license (
CC BY-NC 4.0).
  • Home
  • About
  • Contact