MrRubix's Riddle Thread - Page 2

wwwJ4mmYcouk · 08-4-2008, 11:00 AM

Quote:

Originally Posted by MrRubix_MK5

Incorrect

If I said the hands looked like this:

|
|
|_____

What time would you tell me that is?

It can be one of two times...

12:15 or 3.00 ?

**Beethovens mask** · 08-4-2008, 11:00 AM

Quote:

Originally Posted by MrRubix_MK5

Incorrect

If I said the hands looked like this:

|
|
|_____

What time would you tell me that is?

I would say that it is 3 o clock.

Quote:

Originally Posted by wwwJ4mmYcouk

It can be one of two times...

12:15 or 3.00 ?

If it was 12:15 then the top hand would be farther a long. Rubix you are correct.

EDITED: I was being stupid. *slaps head*

MrRubix_MK5 · 08-4-2008, 11:01 AM

Quote:

Originally Posted by wwwJ4mmYcouk

It can be one of two times...

12:15 or 3.00 ?

3:00 would be right.

12:15, not correct. Look at your watch when it's 12:15. Is the hour hand pointing straight up? When the minute hand makes a full rotation, does the hour hand suddenly "click" over one hour or does it move gradually with time?

MahouMinachan · 08-4-2008, 11:02 AM

It's only 3:00.

Code:

 |
|
---

This looks more like 12:15.

Edit: If 12 exact is 0 degrees, at 12:15 the hand would be at 90 degrees, but the hour would be at 7.5 degrees.

wwwJ4mmYcouk · 08-4-2008, 11:02 AM

Yer i think i am out of my depth... Back to watching TV

EDIT: Rubix i understand about the hour hand being slightly more at an angle if it is 1/4 past the hour.

**Beethovens mask** · 08-4-2008, 11:06 AM

You can all use this to draw out your examples of time, not little slashs and things.

MahouMinachan · 08-4-2008, 11:09 AM

I'd rather just name angles because it gives exactness.

MrRubix_MK5 · 08-4-2008, 11:12 AM

Incorrect

I am assuming your logic is overlaps minus noon, which is the "initial" answer most people would give at first glance

Fractal_Monkey · 08-4-2008, 11:12 AM

Oops, thought it was a different question the first time. My bad for not reading.

Okay, let m = number of degrees turned by the minute hand (mod 360)
h = number of degrees turned by the hour hand

now, h - m/12 = 0 (mod 30) is always true, so it follows that any time where the statement

m - h/12 = 0 (mod 30) (i)

is true would correspond to a pair of times where the hands can be interchanged.

Now, plugging some values of m and h into a table reveals that m-h/12 increases by 143 every 24 minutes i.e. m-h/12 increases at the rate of 143/24 per minute. The statement (i) holds true every 30*24/143 minutes, or every 5.034965 minutes.

Over a period of 12 hours (720 minutes), there are 143 times where (i) is true. One of these is 12:00, which can be discounted, so that leaves 142 times over 12 hours. For example, 12:05.034... is indistinguishable from 1:00.41958..., and so on.

MrRubix_MK5 · 08-4-2008, 11:28 AM

You're in the right mindset, but, wrong

**rushyrulz** · 08-4-2008, 11:29 AM

Rubix, I edited my post 500 times. Here it is.

http://www.flashflashrevolution.com/...8&postcount=19

P.S. ym barin hruts.

MrRubix_MK5 · 08-4-2008, 11:31 AM

lol, no. There are times where you cannot tell.

**rushyrulz** · 08-4-2008, 11:33 AM

I didn't say there weren't. You can't tell when it's at an 180 degree angle. you can't tell the difference between 12:31 and 6:01, 12:32 and 6:02, 12:33 and 6:03, etc.

Edit: yes you can. I suck at riddles. Leave me alone =(. This is a problem of hour to minute ratios and I'm bad at ratios. so bye.

**hoochan** · 08-4-2008, 12:09 PM

12:00
1:05
2:10
3:15
4:20
5:25
6:30
7:35
8:40
9:45
10:50
11:55
12:00

All of these times are when the minute hand AND the hour hand are in the exact same position.

So, it's 13 if you count the last 12:00 and 12 if you don't.

**EnR** · 08-4-2008, 12:14 PM

Quote:

Originally Posted by hoochan

12:00
1:05
2:10
3:15
4:20
5:25
6:30
7:35
8:40
9:45
10:50
11:55
12:00

All of these times are when the minute hand AND the hour hand are in the exact same position.

So, it's 13 if you count the last 12:00 and 12 if you don't.

These are the times he CAN tell us, I already did the same thing.

He wants to know what times he can't tell us.

**Kynosaur** · 08-4-2008, 12:17 PM

12, because the minute hand would be directly over the hour hand once every hour, right?

MrRubix_MK5 · 08-4-2008, 12:19 PM

12 is wrong.

**Kynosaur** · 08-4-2008, 12:19 PM

Fine then *leaves*

MrRubix_MK5 · 08-4-2008, 12:21 PM

Might be better if you try to explain, mathematically, when you would not be able to tell what time it was. And then use that framework to derive how many such times exist.

ieatyourlvllol · 08-4-2008, 12:26 PM

Oops...I read over the problem too quickly and assumed it was the more traditional coincidental problem (to which the answer has already been given). Yours is slightly more complex than it lends its appearance to. I'll get the solution after lunch. 8)

08-4-2008, 11:02 AM	#24
MahouMinachan FFR Player Join Date: Jun 2005 Posts: 205	Re: MrRubix's Riddle Thread It's only 3:00. Code: \| \| --- This looks more like 12:15. Edit: If 12 exact is 0 degrees, at 12:15 the hand would be at 90 degrees, but the hour would be at 7.5 degrees. __________________ I have a sig. Last edited by MahouMinachan; 08-4-2008 at 11:04 AM..

08-4-2008, 11:02 AM	#25
wwwJ4mmYcouk FFR Player Join Date: Feb 2005 Location: England Posts: 1,031	Re: MrRubix's Riddle Thread Yer i think i am out of my depth... Back to watching TV EDIT: Rubix i understand about the hour hand being slightly more at an angle if it is 1/4 past the hour. __________________ Frank Lee Morris Μήπως πραγματικά πνιγεί;

08-4-2008, 11:09 AM	#27
MahouMinachan FFR Player Join Date: Jun 2005 Posts: 205	Re: MrRubix's Riddle Thread I'd rather just name angles because it gives exactness. __________________ I have a sig.

08-4-2008, 11:12 AM	#28
MrRubix_MK5 Banned Join Date: Jul 2008 Posts: 120	Re: MrRubix's Riddle Thread Incorrect I am assuming your logic is overlaps minus noon, which is the "initial" answer most people would give at first glance

08-4-2008, 11:12 AM	#29
Fractal_Monkey FFR Player Join Date: Apr 2005 Location: Manchester, England Posts: 464	Re: MrRubix's Riddle Thread Oops, thought it was a different question the first time. My bad for not reading. Okay, let m = number of degrees turned by the minute hand (mod 360) h = number of degrees turned by the hour hand now, h - m/12 = 0 (mod 30) is always true, so it follows that any time where the statement m - h/12 = 0 (mod 30) (i) is true would correspond to a pair of times where the hands can be interchanged. Now, plugging some values of m and h into a table reveals that m-h/12 increases by 143 every 24 minutes i.e. m-h/12 increases at the rate of 143/24 per minute. The statement (i) holds true every 3024/143 minutes, or every 5.034965 minutes. Over a period of 12 hours (720 minutes), there are 143 times where (i) is true. One of these is 12:00, which can be discounted, so that leaves 142 times over 12 hours*. For example, 12:05.034... is indistinguishable from 1:00.41958..., and so on.

08-4-2008, 11:28 AM	#30
MrRubix_MK5 Banned Join Date: Jul 2008 Posts: 120	Re: MrRubix's Riddle Thread You're in the right mindset, but, wrong

08-4-2008, 11:29 AM	#31
rushyrulz Digital Dancing! Join Date: Feb 2006 Location: 80 billion club, NE Age: 33 Posts: 12,985	Re: MrRubix's Riddle Thread Rubix, I edited my post 500 times. Here it is. http://www.flashflashrevolution.com/...8&postcount=19 P.S. ym barin hruts. __________________

08-4-2008, 11:31 AM	#32
MrRubix_MK5 Banned Join Date: Jul 2008 Posts: 120	Re: MrRubix's Riddle Thread lol, no. There are times where you cannot tell.

08-4-2008, 11:33 AM	#33
rushyrulz Digital Dancing! Join Date: Feb 2006 Location: 80 billion club, NE Age: 33 Posts: 12,985	Re: MrRubix's Riddle Thread I didn't say there weren't. You can't tell when it's at an 180 degree angle. you can't tell the difference between 12:31 and 6:01, 12:32 and 6:02, 12:33 and 6:03, etc. Edit: yes you can. I suck at riddles. Leave me alone =(. This is a problem of hour to minute ratios and I'm bad at ratios. so bye. __________________ Last edited by rushyrulz; 08-4-2008 at 11:36 AM..

08-4-2008, 12:09 PM	#34
hoochan woah shrooms Join Date: Nov 2005 Posts: 3,838	Re: MrRubix's Riddle Thread 12:00 1:05 2:10 3:15 4:20 5:25 6:30 7:35 8:40 9:45 10:50 11:55 12:00 All of these times are when the minute hand AND the hour hand are in the exact same position. So, it's 13 if you count the last 12:00 and 12 if you don't.

08-4-2008, 12:19 PM	#37
MrRubix_MK5 Banned Join Date: Jul 2008 Posts: 120	Re: MrRubix's Riddle Thread 12 is wrong.

08-4-2008, 12:21 PM	#39
MrRubix_MK5 Banned Join Date: Jul 2008 Posts: 120	Re: MrRubix's Riddle Thread Might be better if you try to explain, mathematically, when you would not be able to tell what time it was. And then use that framework to derive how many such times exist.

08-4-2008, 12:26 PM	#40
ieatyourlvllol FFR Player Join Date: Sep 2006 Location: it's a mystery oooo Posts: 3,221	Re: MrRubix's Riddle Thread Oops...I read over the problem too quickly and assumed it was the more traditional coincidental problem (to which the answer has already been given). Yours is slightly more complex than it lends its appearance to. I'll get the solution after lunch. 8)

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