My watch

small_unicorn

As I traveled up and down our great and glorious country, I found myself in a place where the temperature goes up sharply in the day and down at night. This had an affect on my watch. I noticed it was $\frac{1}{2}$ minute fast at nightfall, but at dawn it had lost $\frac{1}{3}$ minute, making it only $\frac{1}{6}$ minute fast.
One morning - May 1 - my watch showed the right time. By what date was it 5 minutes fast ?

from book "The Moscow puzzles" by Boris A. Kordemsky

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**Posted:** Mon Oct 19, 2009 10:14 am

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$LaTeX$

No!!!!!!!!!!!!!!!!!
Oh Well

**Posted:** Mon Oct 19, 2009 5:53 pm

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Wallbash Red

DOPE!!! I FAIL AT EVERYTHING!!!
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Stank

I would just like to note that you, Small Unicorn, pay WAY to much attention to what time your watch displays. And anyway, if you know the correct time so precisely, why wear a watch?

**Posted:** Mon Oct 19, 2009 6:07 pm

AndrewTom

I enjoyed doing your puzzles, small_unicorn. Do you have any that don't involve telling the time? Thanks.

**Posted:** Mon Oct 19, 2009 11:28 pm

O M G

whats up with all the time problems

**Posted:** Sat Oct 24, 2009 8:19 pm

AdithyaGanesh · Hodge Conjecture Offline Joined: 20 Oct 2009 Posts: 50

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EDIT: I'm probably wrong, but can you explain your reasoning for this:

**Posted:** Sat Oct 31, 2009 10:22 am

PowerOfPi

Err, 30+1=31 and since May has 30 days, it is June 1, right?

**Posted:** Sun Nov 01, 2009 4:54 pm

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gaussintraining · Riemann Hypothesis Offline Joined: 23 Aug 2009 Posts: 272

May has $31$ days. Wink

**Posted:** Sun Nov 01, 2009 4:56 pm

PowerOfPi

Fail. Then it should be May 31.

**Posted:** Sun Nov 01, 2009 5:02 pm

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$LaTeX$

It is May 28.

We know that on May 28, it was 4.5 minutes fast. But before nightfall, it gained .5, making it 5 minutes fast.

**Posted:** Sun Nov 01, 2009 5:21 pm

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Wallbash Red

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PowerOfPi

Where does it say that? I don't see anything about May 28 in the problem.

**Posted:** Sun Nov 01, 2009 5:29 pm

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$LaTeX$

May 28 is the answer..... Yup

Conversation over... Very Happy

**Posted:** Sun Nov 01, 2009 5:38 pm

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Wallbash Red

DOPE!!! I FAIL AT EVERYTHING!!!
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PowerOfPi

Seriously, where did you get May 28 from? Is it your birthday or something?

**Posted:** Sun Nov 01, 2009 6:19 pm

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$LaTeX$

It is the answer, what do you not get.... Mad

See my reasoning (the second post) for how I got it...

People these days, and no it is not my birthday. Wacko

Mods lock.

**Posted:** Sun Nov 01, 2009 6:27 pm

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XxaznlaziiboixX · New Member Offline Joined: 01 Nov 2009 Posts: 2

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**Posted:** Sun Nov 01, 2009 7:11 pm

AndrewTom

I agree with LaTeX.

The watch gains $1$ minute every $6$ days (at dawn). So after $27$ days, at dawn on May $28$ th, it gained $27/6 = 4.5$ minutes. Then by nightfall (still the $28$ th) it gained another $0.5$ minutes, so that it was then $5$ minutes fast - on the $28$ of May.

Sorry, but I can't see how to improve on LaTeX's explanation.

**Posted:** Mon Nov 02, 2009 10:50 am

AndrewTom

Hi small_unicorn. Would still like to see other puzzles from your book (that aren't about time).

**Posted:** Mon Nov 02, 2009 12:01 pm