Jump to content
BrainDen.com - Brain Teasers
  • 0
bonanova

100 coins. Some of them are fake

Question

You have 10 sets of ten coins. One set of the ten is counterfeit, the others are genuine. The genuine coins weigh exactly 0.10 ounces. The counterfeit coins are exactly a 0.01 ounces off, making the entire set of ten coins 0.10 ounces off. You may use an extremely accurate digital scale only once. How do you determine which set is counterfeit?

Share this post


Link to post
Share on other sites

1 answer to this question

  • 0
Spoiler

Let's label the sets #0 through #9. Place 0 coins from set #0, 1 coin from set #1,  2 coins from set #2… etc… through 9 coins from set #9 on the scale, all at once. The hundredths digit on the scale display tells you which of the ten sets is counterfeit.

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×