perplexus.info :: Weights and Scales : 9 coins prob

9 coins prob (Posted on 2016-01-18)

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.)

re: Two preplanned weighings

| Comment 5 of 6 |

(In reply to Two preplanned weighings by Brian Smith)

Excellent, elegant approach!

Unfortunately, this specific preplanned weighing fails, because 1+3+7 < 2+5+6.

However, it would work if the 2nd weighing was 2+3+7 vs 1+5+6

Posted by Steve Herman on 2016-01-19 07:59:35

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