Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

The Sciences

Fuzzy Math: Heavy Eggs

Make sure to weigh all the information.

By Alex StoneApril 28, 2007 5:00 AM

Newsletter

Sign up for our email newsletter for the latest science news

Let’s say you are given nine identical-looking eggs and told that one is heavier than the others, but you aren’t told which one. Fortunately, you have a beam balance for comparing the masses of the eggs. Unfortunately, the balance is a rental, and you are being charged each time you use it.

So assuming you are strapped for cash and wish to know which of the nine eggs is heaviest—who wouldn’t?—what is the minimum number of times you must weigh the eggs in order to find it?

The answer, it may surprise you to learn, is only twice. Here’s how: First divide the eggs into groups of three and compare the masses of two groups; if one trio is heavier, simply compare two eggs from that one and you’re done. On the other hand, if the two triplets you weighed have the same mass, compare two eggs from the trio you initially left out.

2 Free Articles Left

Want it all? Get unlimited access when you subscribe.

Subscribe

Already a subscriber? Register or Log In

Want unlimited access?

Subscribe today and save 70%

Subscribe

Already a subscriber? Register or Log In