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Ninety nine coins plus one catch (Posted on 2014-06-01) Difficulty: 3 of 5
You are given a task of locating one faulty coin out of 99 identical in appearance coins i.e. 98 of equal weight and one of a lesser weight; and to achieve it within seven weighings, using a balance scale.

Sounds familiar and easy (37>99)?

Familiar? Yes.

Easy? Not quite!

How can you accomplish it if no coin may be weighed more than twice ?

Bonus task: After devising the requested procedure please generalize:
How many coins (n-1 normal and one lighter) can be resolved within k weighings?

No Solution Yet Submitted by Ady TZIDON    
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Comments: ( Back to comment list | You must be logged in to post comments.)
Hints/Tips re: Any thoughts on this one? | Comment 3 of 7 |
(In reply to Any thoughts on this one? by tomarken)

What would you prefer?

a. a solution

b. a hint (like 1st set of marbles }

c. the methodology

d. the story of my error (BTW 96+1 is solvable)


I will gladly cater to your choice, believing that each of the above

will lead you to correct solution. 


  Posted by Ady TZIDON on 2014-07-02 02:46:21
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