Riddle of the Week

Riddle of the Week: The Burning Rope Problem

Difficulty level: Moderate

Michael Stillwell
 
By Jay Bennett

We're back with another riddle, and this week's is nice and short, though figuring out the solution can be a bedeviling pursuit.

PROBLEM

You have two ropes coated in an oil to help them burn. Each rope will take exactly 1 hour to burn all the way through. However, the ropes do not burn at constant rates—there are spots where they burn a little faster and spots where they burn a little slower, but it always takes 1 hour to finish the job.

With a lighter to ignite the ropes, how can you measure exactly 45 minutes?

HINT

You can light multiple ends and/or multiple ropes at the exact same time.