Puzzling Stack Exchange
Puzzling Stack Exchange

Questions tagged [time]

Puzzles which include the concept of time, as for instance: clocks, dates, calendars, conversions from one time zone to another, time-intervals.

130 questions
55
votes
12 answers

A clock correct three times a day

A stopped clock tells the right time twice a day. How fast must a clock go for it to be right three times a day?
Simd
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24
votes
3 answers

Digital Clock Brightness

My alarm clock has a typical 7-segment digital display showing hours and minutes. Every lit segment is equally bright, and every unlit segment is equally dark. The separator (:) is always lit. Assuming the clock uses 12-hour time without a leading…
zennehoy
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24
votes
1 answer

Aging A Lot Faster

The day before yesterday, I was 20 years old, and next year I will turn 23. What day is it today? Note: This is not lateral-thinking, and the solution is real and makes sense.
Lifesaving Linen
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18
votes
5 answers

You cannot have 120 degrees of separation, but how close can you get?

If you take a look at a standard three-hand gear-driven analog clock, there is never(see footnote) a time of day where the hands of the clock divide the face equally into 120 degree segments, but you can get close. What's the nearest set of angles…
Caius Jard
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16
votes
1 answer

The Odd Street Clocks

The clockmaker took a walk after a lunch from a restaurant and across the block corner he found the old clock box with four similar looking clocks on every wall. It is in the middle of the street intersection mounted on top of a tall wooden pole.…
TSLF
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9
votes
2 answers

Where are you at this time

Where are you if, When it's 10 o'clock, it's 2 o'clock When it's 5 o'clock, it's 7 o'clock
Jason P Sallinger
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5
votes
3 answers

A Second Hand Question

" It is a very simple question", said Grandpa " Look at that wall clock and tell me exactly how many times the Second Hand passes directly over the Minute and the Hour Hands in a 24 hour period. Give me the total times the Second Hand is…
DrD
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4
votes
3 answers

Doing Time In Prison

A prisoner was awoken by an earthquake that caused his wall clock to fall to the floor and rolled in the corner of his cell. When the ground stops shaking, he learns that the clock is still working properly. He can hear it ticking but all he can…
TSLF
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3
votes
2 answers

Digital Alarm Clock

Most of the alarm clock's bulbs are busted as shown above in black shades. Although still working it is not possible to tell what time is it. If we can fix it to display a pattern every seconds, maybe it will be possible to tell time. How can it…
TSLF
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2
votes
3 answers

Safety Fuses and Matches

You have 2 safety fuses and 4 matches. Each fuse takes exactly one hour to burn, but they are not perfect so may not necessarily burn evenly from both sides. For example, the first half might burn in 20 minutes and the second half might take 40…
Oray
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0
votes
1 answer

Measure time with 2 ropes

You are given two ropes that when lit burn in one hour. Which one of the following time periods CANNOT be measured with your ropes? a) 50 min b) 30 min c) 25 min d) 35 min. I know 30 minutes is definitely possible as we could burn the rope at both…
quantrader23
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-1
votes
1 answer

When was Sia born?

John was born on 15 August 2007. If Sia is 17 year older than John. On which day Sia was born? Tuesday, Wednesday, Monday, Friday
user57041
-3
votes
1 answer

Daylight And Standard Time Not Equal Timespan Yet Works Out

I have been thinking about this for a long time now, and no one can answer it. I forget the exact length span, however, the span for each is not equal. For example, DST is 120 days, and "standard" time is 245 days. It would seem, since DST and…
MaxThrust
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-3
votes
1 answer

Two burning ropes measure 5 minutes

Today I was at a job interview and the last question was, "How can I measure 5 minutes by lighting two ropes that each take an hour to burn but do not burn uniformly?" (classical). I know how to measure 15 minutes and 45 minutes, but 5 minutes....?
user32000
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-3
votes
3 answers

How to restore the scrambled master clock?

I don't know how the master clock, with which other clocks in the world are synchronized, is setup. who decided the mechanism used to setup the master clock when the master clock was setup how to restore the master clock in case all clocks in…
Display Name
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