39 coins / 120 coins / 29523 coins. Whatever you like.

So, when the '12 coins' riddle ('by engiin', here in Poland we call it "Maharaja's balls") is solved, let's try something bigger:

There are 39 identically-looking golden balls, but one of them is fake and has a different weight: it is either lighter, or heavier. You have to find that ball.

You have a balance scale at your disposal, but you can use it only 4 times.

Or, if you are more ambitious - find one of 120 in 5 weighings!

Don't worry, it is possible. It is even possible to find one of 29523 in 10 weighings

It IS easy... when you know HOW to solve it

Have fun!

More HARDER riddles still to come!

Cheers.