It’s the Friday Puzzle!

 

A very different type of puzzle this week.  I have just made this video containing 10 bets that you will almost win (kinda).  About 1 min in I present one of my favourite puzzles – the vanishing square.

You can download your own version of the puzzle here.

So, the puzzle is….why does a square seem to vanish?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

Answer to the Friday Puzzle!

97

cover

On Friday I set this puzzle…

Imagine the Earth is perfectly circular and has a circumference of 24,000 miles.  If you had a piece of rope stretched around it, touching the floor, that rope would also be 24,000 miles long. If you were to add 3 feet to that rope and then make it hover above the ground until it’s a perfect circle again, approximately how far off the ground would it get?

If you have not tried to solve it, have a go now.  For everyone else the answer is after the break….

 

Continue reading

It’s the Friday Puzzle!

cover

Here is a lovely puzzle sent to me by Ashley F.  Solution on Monday.

Imagine the Earth is perfectly circular and has a circumference of 24,000 miles.  If you had a piece of rope stretched around it, touching the floor, that rope would also be 24,000 miles long. If you were to add 3 feet to that rope and then make it hover above the ground until it’s a perfect circle again, approximately how far off the ground would it get?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

It’s the Friday Puzzle!

cover

Solution on Monday.

What do the following words have in common?

DEFT
FIRST
CALMNESS
CANOPY
LAUGHING
STUPID
HIJACK

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

Answer to the Friday Puzzle…

34

cover

On Friday I set this puzzle….

Imagine a test with 26 questions.  When you get a question wrong you are deducted 5 points.  When you get a question right you are given 8 points.  If you answered all of the questions, and had a final score of 0 points, how many questions did you answer correctly?

If you have not tried to solve it, have a go now.  For everyone else the answer is after the break.

Continue reading

It’s the Friday Puzzle!

13

cover

Solution on Monday.

Imagine a test with 26 questions.  When you get a question wrong you are deducted 5 points.  When you get a question right you are given 8 points.  If you answered all of the questions, and had a final score of 0 points, how many questions did you answer correctly?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

Answer to the Friday Puzzle….

81

cover

First, if you are around Edinburgh, I am giving a talk tonight at the International Magic Festival on the psychology of magic and illusion.  Details here.

Second, on Friday I set this puzzle…

A long playing record has a 12 inch diameter.  The unused bit in the middle is about 4 inches in diameter, and there is a smooth outer edge one inch wide around the recording.  If there are 91 grooves to the inch, roughly how far does the needle move during the recording?

If you have not tried to solve it, have a go now.  For everyone else the answer is after the break.

Continue reading

It’s the Friday Puzzle….

cover

Solution on Monday.

A long playing record has a 12 inch diameter.  The unused bit in the middle is about 4 inches in diameter, and there is a smooth outer edge one inch wide around the recording.  If there are 91 grooves to the inch, roughly how far does the needle move during the recording?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

It’s the Friday Puzzle!

cover

Solution on Monday.

A shop sells chocolates for £1 each, and you can exchange 3 wrappers for 1 chocolate. If you start off with £15, how many chocolates can you buy?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.