Urban Salvaged Hardwood Slabs, Milled In-House from Rare Trees. Shop Unique Walnut Stock.
Articles Forums Gallery Marketplace Videos

WoodCentral Forums

Est. 1998 — 27 years of woodworking knowledge

Find sources of lumber, veneer, wood specialties and sawmill services - see how it works

Puzzle -- Red and Blue Balls

Posts

Puzzle -- Red and Blue Balls

#1

Puzzle -- Red and Blue Balls

Alex Y

This is an easier one as a brief respite from the self-describing sentence.

I have 60 red balls and 60 blue balls. They are all identical except for color. I have three identical boxes.

I put 40 red balls in one box, 40 blue balls in a second box, and 20 of each in the third box. I label the boxes "red", "blue", and "mixed", but in each case the label on the box is wrong.

You are allowed to examine one ball from one of he boxes. Can you then correctly label all three boxes? How or why not?

Re: Puzzle -- Red and Blue Balls

#2

Re: Puzzle -- Red and Blue Balls

Larry Barrett

All three boxes are mislabeled. So pick a ball from the box now labeled mixed. It must hold either the blue balls or the red balls. Suppose it is blue. You now know that all the balls in this box are blue. The box now labeled blue must actually hold the red balls and the box now labeled red must be the mixed box. Move all the labels to the correct boxes.

Re: Puzzle -- Red and Blue Balls

#3

Correct 😄


👍 This page answered my questions

Your vote helps other woodworkers quickly find the answers and techniques that actually work in the shop.