FOOD FOR THOUGHT

Brainteaser

The Infinite Quarter Sequence: You have an infinite number of quarters (25-cent coins) arranged in a line. Every minute, you flip every second coin (starting with the second one). Then, every two minutes, you flip every third coin. Every three minutes, you flip every fourth coin, and so on. After an infinite amount of time, which coins are face up?

Want to read this article?

Subscribe to access Deep Dive articles, book reviews, podcasts, Ask the Founder, and access to our members-only forum.

Become a Member

Already a subscriber? Sign in