I’m going to give you a little problem to test your powers of logical thinking.

It’s what we call a minimum information problem.

OK? Let’s go!

 

Now in a room are several sacks of gold pieces.
As many sacks as you like.
Each sack contains several of these gold pieces.
Again as many as you like.

 

One sack, however, is full of artificial gold pieces,
and they weigh differently.

 

Now, the solid gold pieces weigh… oh, let’s say a pound each.
And the artificial pieces weigh whatever you like.

 

Now, you have a penny scale.

(So I put a penny in, and I get a card and that tells me how much the weight of the gold is.)

 

Exactly. But you only have one penny.
Now, which sack has the artificial gold pieces?