This triangle is constructed from 10 coins. What is the smallest number of coins that need to be moved to make the triangle point downwards?
As ever, please do NOT post your answers, but do say whether you think you have solved it 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.
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July 22, 2011 at 6:02 am |
Feel very easy, done in about 20 seconds
July 22, 2011 at 6:03 am |
Took me about 2 seconds. Assuming I’m right…
July 22, 2011 at 6:51 am
Same.
July 22, 2011 at 2:22 pm
I didn’t even finish the question
very old puzzle that I have seen many times before.
July 22, 2011 at 6:04 am |
Done it. 1 minute.
July 22, 2011 at 6:06 am |
Done in about 5 seconds.
July 22, 2011 at 6:06 am |
If I’m right — about 30 seconds.
July 22, 2011 at 6:06 am |
Are they 5p or 10p pieces?
July 22, 2011 at 2:37 pm
ROFL
July 22, 2011 at 6:09 am |
Done – in about 20 seconds.
July 22, 2011 at 6:12 am |
Done. But I think my answer is cheating kind of. about 10 seconds.
July 22, 2011 at 6:12 am |
Yep, 20-30 seconds.
July 22, 2011 at 6:13 am |
Seen it before, took 3 seconds back then too.
July 22, 2011 at 6:16 am |
Got one solution in 5s but another improved one in another 2-3 minutes.
July 22, 2011 at 6:18 am |
easy! 10 seconds
July 22, 2011 at 6:23 am |
Not too long today but only if I got the correct answer
July 22, 2011 at 6:26 am |
10 seconds. Maybe too easy? I guess I’ll find out monday…
July 22, 2011 at 6:32 am |
Instantly…
Hope i’m right.
July 22, 2011 at 6:45 am |
got it,took a couple of seconds (hope i’m right)..
July 22, 2011 at 6:48 am |
Yes, fairly easy (for a change).
July 22, 2011 at 6:48 am |
Depending on how you read the question, 2 solutions in a few seconds
July 22, 2011 at 8:36 am
Read it again. The problem asks for the smallest number. That means that there is only one solution.
July 22, 2011 at 12:47 pm
There is only one solution, however what that is depends on how you interpret Richards question…
July 22, 2011 at 6:53 am |
About 30 seconds. If I’m right.
July 22, 2011 at 7:14 am |
Done in a couple of seconds (I think!)
July 22, 2011 at 7:15 am |
about 5 sec assuming i am right. i think even two possibilities based on how its worded
July 22, 2011 at 7:23 am |
Did this quickly but then I have seen it before.
July 22, 2011 at 7:32 am |
Well, I think I-ve done it, but there may be a better answer, I just haven-t found it.
Anyway, depending on how you look at it, the triangle could already be pointing downwards left or downwards right.
July 22, 2011 at 7:48 am |
None, you just have to view it in an Australian frame of reference…
Harder next time please
July 22, 2011 at 7:49 am |
Got it instantly.
July 22, 2011 at 7:53 am |
but it already points downwarts.. in a rightish downwards direction and in leftish downward direction. …
If you want it to point straigth down, … also possible, 3 seconds..
without moving the upper and lower boundaries of the triangle an additional coin is required to be moved..
July 22, 2011 at 7:57 am |
I got one answer in about 5 seconds, then a correct answer about a minute or two later.
July 22, 2011 at 7:58 am |
sorry, have anohter (presumably incorrect solution).. after a few minutes.. definitivly including the minimum of coins to be moved…
July 22, 2011 at 8:00 am |
About a minute. Couldn’t find 10 similar coins though!
July 22, 2011 at 8:02 am |
See, I think I’ve done it and it was far too easy so no doubt on Monday the answer will be something like ‘π x happiness’
Oh how Mondays make me feel stupid.
July 22, 2011 at 8:18 am |
That was too easy. 2 seconds.
If someone get’s less that that though, I’ll be *really* impressed
July 22, 2011 at 8:34 am |
Done! Three seconds! (Although I had the feeling I had seen something similar somewhere…)
July 22, 2011 at 8:39 am |
Got it wrong in about twenty seconds.
Got it right in a further twenty and made a 25% saving….
July 22, 2011 at 8:42 am |
About 5 seconds, assuming I am right… I can’t find an alternative with fewer moves.
July 22, 2011 at 8:48 am
It must be right.
July 22, 2011 at 8:50 am |
!
July 22, 2011 at 9:22 am |
Solved this in 0.1237 seconds
July 22, 2011 at 9:25 am |
I’ve seen it before, so about 1/2 s after seeing the illustration.
July 22, 2011 at 9:36 am |
I solved it yesterday
July 22, 2011 at 9:37 am |
About 30 secs to get one answer and then about another 45 secs to get a better one.
July 22, 2011 at 10:16 am |
Two solutions in 10 seconds. Because the puzzle is old, or because I am.
July 22, 2011 at 11:24 am |
Too easy, how about fewest moves to a dodecahedron? or a rabbit? or hyperlipoproteinurea?
July 22, 2011 at 11:25 am |
it can be done in no moves- just walk around to the other side of the table
July 22, 2011 at 12:00 pm
That’s exactly what I was going to say.
July 22, 2011 at 12:16 pm |
there is the obvious way and then the trick which we normally miss – i advise people to recount their moves before monday
July 22, 2011 at 2:24 pm |
Your link to the free puzzles is giving a Error 404 – Not Found page.. . .Hey, wait a minute. Is that the puzzle? I’m confused.
July 22, 2011 at 2:40 pm |
I too got a quick answer in a few seconds and then improved it with a minutes thought.
July 22, 2011 at 2:55 pm |
Done it. Half-a minute? I’m quite sure.
July 22, 2011 at 2:58 pm |
Good old Professor Layton taught me this one.
July 22, 2011 at 3:04 pm |
simple….but perhaps I’m just very bright!
July 22, 2011 at 3:04 pm |
I see 2 possible answers. There is also an interpretive shade of grey in the possible answer.
July 22, 2011 at 3:22 pm |
Really? That took a couple of seconds to work out.
July 22, 2011 at 3:30 pm |
It took me about a minute to see the core pattern. I will check in on Monday to see if I got the correct answer.
July 22, 2011 at 5:43 pm |
0s
July 22, 2011 at 6:30 pm |
Very quickly, think I’ve seen it before tbh. (Nothing wrong with that though)
July 22, 2011 at 7:23 pm |
Isn’t it already pointing downwards? If you assume that one of the bottom corners of the triangle is the point. 5 seconds.
July 22, 2011 at 9:20 pm |
Depends on the exact rules. I found three different solutions, took me about 1 minute for all of them.
July 22, 2011 at 9:30 pm |
5 secs
July 23, 2011 at 10:15 am |
If you are able to see the shape not as a triangle, but a composite of two items (one which will remain unchanged) the answer jumps out at you.
July 24, 2011 at 10:16 am |
Zero: I turned my laptop around…
July 24, 2011 at 4:26 pm |
Again I don’t think this has anything to do with maths, but I’m going to pretend and have a shot.
July 24, 2011 at 4:27 pm |
Ah. I got one answer in about 20 secs, but then spent another minute seeing if I could find a better one. I believe I have the right answer now. Can’t see a better solution
July 24, 2011 at 8:47 pm |
About 2/3 seconds. And looking into the future, I can see it’s right, so fairly confident…
July 25, 2011 at 5:26 am |
Two answers – one involving three coins fewer than the other.