[OK]

Privacy Policy + T&C

We use cookies to personalise our content and adverts. Information about your use of our site is shared with our advertising providers. You also agree to our terms and conditions (T&C).

BB Logo
Spacer
Line
Line

Puzzle - Answer

Suppose I flip two coins, without letting you see the outcome, and I tell you that at least one of the coins came up heads, what is the probability that the other coin is also heads?

 [Ref: ZUYC]

Answer: 1/3.

You might initially think that the answer is 1/2, however, it isn't.

Before I tell you anything, all you know is I've flipped two coins, and the possible outcomes are:

HH, HT, TH, TT

I now tell you that there was at least one head, which eliminates TT, leaving three possibilities. Of these three possibilities, only 1 allows the second head: HH. So the probability is 1/3. QED.

Back to the puzzles...


Our Favourite Illusions

 Shadow Illusion

 What Am I?

 Hidden Faces

 Impossible Waterfall?

 Same Eyes?

 Impossible Prongs?

 Duck Or Rabbit?

 Spinning Dancer

 Who Turned To?

 Blind Spot

 The Butterfly

 Parallel Cafe Wall Lines?

 

 



We use cookies to personalise our content and adverts. Information about your use of our site is shared with our advertising providers. For more information please view our privacy policy. By using the site you also agree to our terms and conditions.

Line
Line