On Friday I posted this puzzle…..
Two trains start at the same time, one from London to Liverpool, the other from Liverpool to London. If they arrive at their destinations one hour and four hours respectively after passing one another, how much faster is one train running than the other?
If you have not tried to solve it, have a go now. For everyone else, the answer is after the break. Continue reading
Here is today’s little puzzle….
Two trains start at the same time, one from London to Liverpool, the other from Liverpool to London. If they arrive at their destinations one hour and four hours respectively after passing one another, how much faster is one train running than the other?
As ever, please do NOT post your answers, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.
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.
Lots of people have been kind enough to send me this great photo….
Can you work out what is going on?
First of all, tickets for the next Edinburgh Secret Society event will go on sale at 10am today. But be quick, because we expect to sell out quickly. Details here.
Second, I haven’t seen this illusion before, and it is great. When the paper squares are on the screen the lines look like they form a square moving in a circular motion. However, remove them and a very different picture emerges.
Like it?
In Paranormality I described how we are all really good at ascribing intentions and emotions to inanimate objects. The other day I came across this great video of a slinky on a treadmill….
What word comes to mind when you watch the slinky? Post your answer as a comment and let’s see if we all come up with the same words.
On Friday I set this puzzle….
Last night seven of my friends went to a local restaurant. They each handed over their coat as they entered. At the end of the evening the staff returned the coats, but they were totally incompetent and randomly handed out the coats to my friends. What is the probability that exactly six of my friends received their own coat?
If you have not tried to solve it, have a go now. For everyone else the answer is after the break.
Last night seven of my friends went to a local restaurant. They each handed over their coat as they entered. At the end of the evening the staff returned the coats, but they were totally incompetent and randomly handed out the coats to my friends. What is the probability that exactly six of my friends received their own coat?
As ever, please do NOT post your answers, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.
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.
Matt Harris kindly brought my attention to a great site containing lots of double take photos…..here are my favourite three…..
I strongly urge you to check out the other here. Which is your favourite?
Everyone and their dog have been kind enough to send me this wonderful video – stare at the cross, hit play, and see celebs as you have never seen them before….
Did it work for you? The illusion was created by Jason Tangen, Sean Murphy and Matthew Thompson from The University of Queensland, and was awarded 2nd place in the 2012 Illusion of the Year thingy.
Mathematician and ace puzzler Martin Gardner died two years ago today. I thought it would be good to use the occasion to celebrate his work with a little YouTube video, and this is what I came up with….
Any idea about the solution? Feel free to spread the word!
On Friday I set this puzzle…..
I am a member of a club in which every member either always lies or always tells the truth. Yesterday I had a telephone call from a member who always tells the truth and he said ‘Some members have just had dinner around a circular table, and each member said ‘I declare that the man on my left is a liar’”. Ten minutes later I received another telephone call from another member called John, and he said “I was at the dinner and there were 11 of us there”. Ten minutes after that I received yet another telephone call from a member called Tim, and he said “I was at the dinner and there were 8 of us there”. Either John or Tim was lying. But who was the liar?
If you have not tried to solve it, have a go now. For everyone else, the answer is after the break.
I am a member of a club in which every member either always lies or always tells the truth. Yesterday I had a telephone call from a member who always tells the truth and he said ‘Some members have just had dinner around a circular table, and each member said ‘I declare that the man on my left is a liar’”. Ten minutes later I received another telephone call from another member called John, and he said “I was at the dinner and there were 11 of us there”. Ten minutes after that I received yet another telephone call from a member called Tim, and he said “I was at the dinner and there were 8 of us there”. Either John or Tim was lying. But who was the liar?
As ever, please do NOT post your answers, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.
I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for theKindle (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.
As you have probably worked out by now, I am a fan of pareidolia. Yesterday I was sent this great photo….
It was taken by ace photographer Matthew Horwood, who very kindly gave me permission to post it here. It gets my vote as the most unusual pareidolia I have seen. What do you think?
This is an animated version of a lovely old Victorian puzzle. Basically, you have to count the number of people in the image, wait for the piece to flip around, and count them again. The flip should happen after about 10 seconds (if it doesn’t, you might have to click on the image and have it open in a separate window)
My thanks to @DrBrocktagon for bringing it to my attention. 10 points to anyone who can explain why it works!
