[OK] Privacy Policy  -  Terms & Conditions  -  See DetailsWe use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners who may combine it with other information you've provided to them or they've collected from your use of their services.

Puzzle Details

Mr Smith has lots of pound coins, ten boxes in all. Each box contains 100 pound coins, but one box contains coins which are all counterfeit and are slightly lighter, 1/16 of an ounce lighter to be exact.

The problem lies in the fact that they all look identical, the only way to tell them apart is to weigh them.

Mr Smith knows the correct weight for a box, but how many weighings are required to determine which box contains the counterfeit ones?

[Ref: ZJYH]

Hint: The answer is a lot less than 100 weighings.

Our Favourite Illusions

 Shadow Illusion Are the squares A and B the same colour? Spinning Dancer Which way is the dancer spinning? Impossible Waterfall? Is the water flowing uphill in this impossible Escher type waterfall? The Butterfly A colourful butterfly?
 Duck Or Rabbit? Is this a duck or a rabbit? Hidden Faces Can you find his three daughters as well? Blind Spot An amazing demonstration of your blind spot. Impossible Prongs? Impossible prongs?
 What Am I? Can you tell what this is a picture of? Who Turned To? Who is missing? Same Eyes? Are her eyes the same colour? Parallel Cafe Wall Lines? Are the horizontal lines parallel?