ADSR

[Bruin Fisher]

Any perfectly ordinary 12 hour analogue clock or watch face will do!

Bruin

[Camy]

Any perfectly ordinary 12 hour analogue clock or watch face will do!

Bruin

and with this there is something you can do 22 times?

Erm ... Look at it! Obvious!

[Bruin Fisher]

and with this there is something you can do 22 times?

Erm ... Look at it! Obvious!

No, Silly! That's called clock-watching and you never do it 'cos your life is so full and exciting....

This event happens exactly 22 times every day whether you like it or not. (Unless the clock is broken, of course - in which case it tells EXACTLY the right time twice every day).

Bruin in mischievous mood - padlock your dustbins! (garbage cans)

[Kapitano]

The usual answer is that the minute hand crosses the hour hand.

But it doesn't really stand up to analysis. The idea is that the first crossing at midnight (0000 hours) doesn't count because that crossing belongs to the previous day, and the final crossing (at the next 0000 hours) belongs to the next 24 hour period, which entails a contradiction if you say the event happens on each consecutive day.

[Trab]

Exactly, Kapitano. That's why I didn't suggest that as the answer.

[Cole Parker]

And on this side of the big pond, we spell it 'synaesthesians'

Bruin, Bear

On this side of the pond we don't spell it at all.

Even looking it up was difficult, but I perservered. Now, if I ever have a use for that word, all I'll have to do is remember it.

Both are unlikely.

Cole

[Bruin Fisher]

The usual answer is that the minute hand crosses the hour hand.

But it doesn't really stand up to analysis. The idea is that the first crossing at midnight (0000 hours) doesn't count because that crossing belongs to the previous day, and the final crossing (at the next 0000 hours) belongs to the next 24 hour period, which entails a contradiction if you say the event happens on each consecutive day.

If you want to start at midnight, you have to count EITHER the first or last crossing as part of the current day, but not both. It's easier to visualise it if you take a 24 hour period starting and ending sometime other than midnight. Say, a minute past midnight - move the minute hand on one hour and it hasn't crossed the hour hand. But in the next hour it will, and so on until after 12 hours it has crossed the hour hand 11 times, and after 24 hours it crosses it 22 times. Try it - it works. And works for ANY 24 hour period.

Bruin

[Kapitano]

Yes, the point is it works for any 24 hour period, not considering the periods before and after. The original question was:

What event takes place on a clock face twenty-two times per day?

That is, "What occurs twenty two times each and every consecutive 24-hour period?" Your solution requires that the final passing be discounted from today's 24 hours and shunted over to become the first passing in tomorrow's 24-hour period, but once we get to tomorrow, the same passing event is shunted back into the previous day, so as not to count.

It's slight of hand, like counting two Sundays to prove that there's eight days a week. In this case, we can see how the magician moves the cards, and the trick is exposed.

[Trab]

Not to be a complete ass--le, but there was no specification about it occurring ONLY 22 times. We could, correctly, say the second hand passes over the minute hand and the hour hand 22 times, ignoring the other multiple number of times it does so.

[Bruin Fisher]

Yes, the point is it works for any 24 hour period, not considering the periods before and after. The original question was:

That is, "What occurs twenty two times each and every consecutive 24-hour period?" Your solution requires that the final passing be discounted from today's 24 hours and shunted over to become the first passing in tomorrow's 24-hour period, but once we get to tomorrow, the same passing event is shunted back into the previous day, so as not to count.

It's slight of hand, like counting two Sundays to prove that there's eight days a week. In this case, we can see how the magician moves the cards, and the trick is exposed.

It isn't anything to do with sleight of hand or discounting midnight passes. The point is that the minute hand passes over the hour hand not once per hour but once every 1 hour 5 minutes 27 seconds. Or 11 times every 12 hours.

If we start with my previous example, begin at 00:01. The first time the minute hand passes over the hour hand is not 01:01, it's actually 01:05:27. The next time they pass is 02:10:54. During the first 12 hours the two hands pass at these times:

01:05.45 (for convenience, 27 seconds is .45 minutes)

02:10.91

03:16.36

04:21:82

05:27.27

06:32.73

07:38.18

08:43.64

09:49.09

10:54.55

12:00

... and during the next 12 hours they will pass another 11 times. QED.

Now my brain hurts and I'm ducking out of this, I'm sorry I ever posed this puzzle! If we're not in agreement now, can we agree to disagree?

Hugs to all

Bruin

[Trab]

Hey, don't worry about it Bruin. Nobody's mad at you. It was intriguing as hell, and fun to see the different perspectives.

[Kapitano]

the minute hand passes over the hour hand not once per hour but once every 1 hour 5 minutes 27 seconds.

Ah. Of course. How could I have missed that?

Nice one.

[Madrigal]

More please, more! And to answer Bruin's 'survivor' riddle... survivors don't get buried!

Maddy (:

[Camy]

But ... but ... I thought clocks were for telling the time?

[Madrigal]

Sadly, Maddy was wrong. I already knew this information, since my brother married the daughter of a conductor, but I double checked, and you can too.

http://en.wikipedia.org/wiki/Conductor_(transportation) Freight trains DO have conductors.

My answer wasn't based on assuming that it was a freight train lol.

I love riddles. What I have noticed is that most of them force you to use only the information within them, and so if this were a legitimate riddle I can assure you my answer would be correct... LOL. I refuse to lose! :P

Maddy (:

[Kapitano]

But ... but ... I thought clocks were for telling the time?

You might say clocks don't tell the time - they create it.

More please, more!

You've probably met this one before.

A piece of rope is wrapped tightly around the earth's equator. It is 40075 km long. Ignore mountains, seas etc - assume the earth is a smooth sphere. The rope is then lengthened by one metre, and lifted from the surface by a constant amount all around.

How far off the surface is the rope?

A) 30 cm

B) 300 cm

C) .03 cm

[Camy]

You might say clocks don't tell the time - they create it.

So ... I have a time machine?

rope - earth - thinking ....

As Oates once said. 'I may be gone sometime'

[Bruin Fisher]

A piece of rope is wrapped tightly around the earth's equator. It is 40075 km long. Ignore mountains, seas etc - assume the earth is a smooth sphere. The rope is then lengthened by one metre, and lifted from the surface by a constant amount all around.

How far off the surface is the rope?

A) 30 cm

B) 300 cm

C) .03 cm

This one was new to me so I've very much enjoyed working on it. Thanks Kapitano!

I reckon this is all about our friend pi.

The circumference of a circle is its diameter multiplied by pi.

So the diameter of a circle is its circumference divided by pi.

The circumference of our rope pre-extension is 40,075,000 metres

So its diameter according to my spreadsheet is 12,756,268.69 metres. Wikipedia gives it as 12,756,260 metres so we're not far off.

Once we extend it, our rope's circumference is 40,075,001 metres

Now its diameter is 12,756,269.01 metres

- which is .32 metres, or 32 cm greater. This is a surprise to me - I was expecting it to be much smaller, like .03 cm. So thanks Kapitano - I love mathematical surprises!

However, the rope won't be 32 cm off the surface of the planet all round, only 16 cm one one side and 16 cm on the other side so that the diameter is increased by 32 cm.

So my answer has to be

D) None of the above

So I expect I've goofed somewhere. Somebody put me right?

Bruin

[Bruin Fisher]

What am I like?

I guess my street cred is permanently wasted now, what was I thinking of doing longwinded maths in the Flash Fiction forum....?? Duh!

Bruin pink from the neck upwards (from the neck downwards its my business..)

[DesDownunder]

What are you people talking about?

The planet is dying and you guys are worried about a train conductor's briefs?

How terribly, terribly human.

And people wonder why we don't get visitors from other worlds.

::jumps up and swings back into his tree::

Note to Trab and Camy: I don't get the puzzle book thing either.

[Bruin Fisher]

What are you people talking about?

The planet is dying and you guys are worried about a train conductor's briefs?

How terribly, terribly human.

And people wonder why we don't get visitors from other worlds.

You do get SOME visitors from other worlds - I came, didn't I?

Ford Prefect always says you're okay so long as you know where your towel is. Planets die, universes end, but if you're in touch with your towel you don't need to worry. My lawyer says something similar about briefs.

Bruin

[DesDownunder]

You do get SOME visitors from other worlds - I came, didn't I?

Ford Prefect always says you're okay so long as you know where your towel is. Planets die, universes end, but if you're in touch with your towel you don't need to worry. My lawyer says something similar about briefs.

Bruin

You have a lawyer AND your from another world?

Things just got worse.

[Bruin Fisher]

You have a lawyer AND your from another world?

Things just got worse.

Oh yes... The Hitchhiker's Guide says never visit a galaxy beyond the limits of civilisation without reliable legal representation...

[DesDownunder]

Oh yes... The Hitchhiker's Guide says never visit a galaxy beyond the limits of civilisation without reliable legal representation...

Well that explains why we have so many laywers on this planet.

[Kapitano]

the diameter is increased by 32 cm.

So my answer has to be

D) None of the above

My maths has always been rubbish, but lets see.

c1 is the circumference of the rope before extension, and thus the circumference of the earth.

c2 is the circumference of the rope after extension.

r1 is the radius of c1.

r2 is the radius of c2.

c1=40075km=40075000m

c2=40075001m

c=2*pi*r, therefore r=c/(2*pi)

r1=c1/(2*pi)

=40075000/(2*3.14)

=40075000/6.28

=6381369.42

r2=c2/(2*pi)

=40075001/(2*3.14)

=40075001/6.28

=6381369.58

Oh bugger. This last stage is where I made a mistake in calculation earlier. Right method, wrong numbers. I told you my maths was rubbish.

r2-r1=0.16

So the difference between the radius of the two circles is 0.16m, which is 16cm.

My apologies. Again. But yeah, you got it right.

PS. Speaking of H2G2, the above is explained here.