Math Challenge Problem
The Math Challenge problem has returned to UNC's School of Mathematical Sciences! This is a problem that everyone is welcomed to try their hand at. New problems twice a month.
November Challenge 2
You enter a magical cave to find seven opaque orbs. A wizard tells you that each orb is colored on the inside, and that four or more of the orbs have the same color. Also, when two orbs of the same color are brought into contact with each other, they will glow, revealing the hidden color. If two orbs touch but have different color, nothing happens. The orbs are heavy, so you can only touch two at a time.
The Challenge: What is the least number of comparisons needed to find one of the orbs of the majority color?
Submit solutions to Ross 2239G or by email to email@example.com.
Deadline: Friday, December 13
New this semester: PRIZES! A winner will be randomly selected from all correct answers received for each challenge problem to receive a fun math prize of his or her choice.