All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Logic > Weights and Scales
9 coins prob (Posted on 2016-01-18) Difficulty: 3 of 5
There are nine silver coins marked 1, 2, 3, 4, 5, 6, 7, 8, and 9.
They are supposed to weigh the number of grams that is written on them.
One of the coins is fake and is lighter than it should be.

Find the fake coin using the balance scale twice.

No Solution Yet Submitted by Ady TZIDON    
Rating: 3.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution Outline of a sample solution | Comment 2 of 6 |
Weigh 169 v 358.

If they balance, the bad coin is in 247.
If left side is light the bad coin is in 169.
If right side is light the bad coin is in 358.

If 247 is bad, weigh 34 v 7. 
Balanced = 2 is bad.
Left light = 4 bad.
Right light = 7 bad.

If 169 is bad, weigh 36 v 9.
Balanced = 1 is bad.
Left light = 6 bad.
Right light = 9 bad.

If 358 is bad, weigh 125 v 8.
Balanced = 3 bad.
Left light = 5 bad.
Right light = 8 bad.

  Posted by Charlie on 2016-01-18 15:50:43
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (13)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information