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75

We'll just apply a bit of science assuming they were born in same year as well:

68

A very simple solution, taking is to A better solution takes only How?

61

Since a stopped clock already agrees with a correctly running clock twice per day, So the answer (that requires the smallest clock hand speed) is Since the answer must be symmetrical (as long as the difference in speeds remains the same, it doesn't matter if our clock is getting ahead or behind the correctly running one), we can get the other answer by ...

58

Hint: You can light both sides of one rope. Solution:

56

50

It is

47

They were born on

46

Apply some other bit of science, assuming they were born at the same time,

45

Foo is older than Bar, but celebrates his birthday the day after Bar because one of the following happened:

37

Is it lateral-thinking?

32

Similar to Daniel's answer but a slight variation:

30

Suppose we have an accurate clock and the fast clock, and that they start off showing the same time. Here is an alternative method:

29

The day is Reasoning: Classic Mind Puzzle :) My fav <3

28

The answer is simply: I have heard this one before but I don't remember where, maybe the movie you mentioned.

26

Let us denote the time by AB:CD:EF, where AB is between 00 and 23, CD and EF are each between 00 and 59, and of course A=F, B=E, C=D. The middle two digits Since C=D and CD ranges from 00 to 59, there are six possibilities: 00, 11, 22, 33, 44, 55. The outer four digits The first two digits (AB) range from 00 to 23. How many of these possibilities give ...

25

24

22 minutes with lateral thinking (though the accepted answer is better)

23

Because they are... And they were born... And...

23

At noon, all three hands are at $0$ degrees from each other. Let's say the Moment of Truth is after the hour hand has moved around $x$ degrees. In that time, the minute hand moves $12x$ degrees and the second hand moves $720x$ degrees. So we want $x, 12x\pmod{360},$ $720x \pmod {360}$ to be separated by $120$ from each other. From the minute and second ...

23

Alternative method: The answer to how fast the clock must go:

22

First produce 48 by putting the traces up/down/up/down/up in the freezer. Then use 18 of the ice cubes and put them in the corners of the botton 6 trays, produce 66 more ice cubes. Do this 2 more times and get 246 in total. Possibly could make 264 if you can balance using 2 cubes only.

21

Would it be because:

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You and your twin were born:

20

It is currently and the older brother is How I figured this out:

20

Logic behind the answer: So, without really looking at anything else, my initial guess is: resulting in: Note: Edit:

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Ok I will present a solution. For convenience, I will number the ropes in the order of their burning. STEP ONE STEP TWO STEP THREE FINAL STEP I have successfully measured 1hour 8 minutes or 68 minutes

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Number of qualifying times: Probability:

18

The date of the accident is Explanation

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There are Because

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The clockface is divided into $60$ segments.

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