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.
100
questions
-3
votes
3answers
169 views
Twisted Timekeeping [closed]
Two office workers need to arrive at work at the exact same time. However that's not likely to happen because the only thing they use for telling the time is their watches and their timekeeping is a ...
3
votes
3answers
227 views
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 ...
1
vote
1answer
116 views
Puzzle storm to infinity
I have been playing Puzzle Storm on Lichess lately. Essentially it involves solving chess puzzles within a given time limit. Additionally, the player gets a time bonus for a certain number of moves. ...
3
votes
2answers
178 views
On which date was Marina born?
The puzzle is as follows:
In 2012, which began on a Sunday, Marina was happy because her birthday was on a Saturday and she celebrated it with her friends. We know, Marina was born in a year where ...
0
votes
0answers
94 views
Nine touching clocks [duplicate]
There are nine 12-hour clocks arranged in a 3x3 grid, as shown in the diagram. The long minute handles of the left two clocks are touching, while the others are not. Two minute handles touch if they ...
9
votes
1answer
1k views
Four touching clocks
There are four 12-hour clocks arranged in a 2x2 grid, as shown in the diagram. The long minute handles of the left two clocks are touching, while the others are not. Two minute handles touch if they ...
1
vote
1answer
284 views
What is the date displayed for the question mark?
Someone sent me these images. It's about the Moon for some reason. Anyways, here are the images:
And also that someone gave me a bonus:
3
votes
1answer
127 views
An altered Alan Parrish question
I was wondering around on Puzzling when I saw this question posted three days ago.
It is a great puzzle and it reminded me me about another puzzle a saw a long ...
6
votes
1answer
184 views
When is the full moon?
During each lunar cycle, the full moon is technically full for one instant, but to the human observer, the moon appears full for 2-3 days and nights in a row, making it hard to tell on which date and ...
10
votes
1answer
351 views
The Alan Parrish question
Two stereotypical british gentlemen that don't know each other engage in this unusual conversation (it's almost as if they were a setup for a puzzle):
Gentleman A - Hello sir, I'll have you know that ...
15
votes
1answer
584 views
Explain this holiday calendar oddity
Happy Boxing Day! Yesterday was Christmas Day, and in a few days, it will be New Year's Day. Each holiday season, those two holidays are always on the same day of the week (in this case, Friday). But ...
3
votes
3answers
186 views
After how many minutes will both hour hand and minute hand lie on one another
The following question was part of my mock test and I was unable to solve it.
Assuming that:
A: The hour hand and minute hand of the clock move without jerking
B: The clock shows a time between 8 o'...
12
votes
0answers
523 views
Qubes: Oh, For the Love Of
TL;DR: This is a mixture between a tribute/spin-off puzzle and an attempt at a new puzzle type, greatly inspired by the notorious arcade game, Q*bert, published originally by Gottlieb Amusement Games. ...
5
votes
3answers
2k views
But wait! We skipped a day!
Today is October 4th and tomorrow will be October 6th. Explain!
Note: I just thought of this one day and decided to post it here. Please don't leave too many downvotes. :(
13
votes
3answers
2k views
A stopped watch shows correct time ---
You know the old saying
A slow or fast running watch is worse than a stopped (broken) watch. At least the stopped watch shows correct time twice a day!
Here is a challenge:
A person was wearing a ...
2
votes
1answer
187 views
Lazy Box Sorting
In front of Louis there are 10 boxes containing different foods: tomatoes, (red) herrings, and bananas.
The boxes are arranged side by side in a line. Right next to the last box are three bigger ...
6
votes
5answers
1k views
Probability of three identical digits on a four-digit digital clock?
On a digital clock showing 00:00 to 23:59, what is the probability of having exactly three identical digits?
16
votes
1answer
538 views
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 ...
1
vote
2answers
152 views
Measure nine minutes with two hourglasses [duplicate]
How can you measure 9 minutes with a 7-minute hourglass and a 4-minute hourglass?
Note: In this question it states where it's possible or not but not the actual procedure for this exact situation.
7
votes
2answers
453 views
Puzzle - Counting Lights, Not Sheep
Some nights it is difficult to get to sleep. On one such night, John counted the
number of LEDs (Light-Emitting Diodes) on his clock radio that was on to make
each individual time from 10:00 PM to 12:...
-1
votes
1answer
176 views
A sensitive lent
The number of days from the first day of Lent to the last day, inclusive, may be best described by:
a) XL
b) Xl + VI
25
votes
1answer
1k views
Using burning ropes as timer - how to measure 1 hour and 8 minutes with 3 ropes?
This is a variation of a well known puzzle, you can find the other versions on PSE.
You have three ropes and a box with ten matches.
As usual each rope takes one hour to burn completely when lighted ...
-4
votes
3answers
143 views
Previous palindrome date
2nd of February this year will be a palindrome date, because 02/02/2020 reads the same forwards and backwards. But when was the previous palindrome date?
5
votes
1answer
244 views
Why do I celebrate later? (still 13,37 years)
A very little time ago, just a bit ago one may say, people started partying. Some even went out of their houses to do so… crazy thing, IMHO.
Anyway, I don't, I'll start partying in 4886 days.¹
Why do ...
4
votes
1answer
357 views
Using burning ropes as timers
This puzzle is an harder version of a very famous one.
It has been asked many times on PSE, but this time the question is slightly different (1) (2). So please read this question twice before marking ...
1
vote
1answer
109 views
Date from 2 wooden cube puzzle [duplicate]
In an interview the interviewer asked me a question based on date.
Suppose in a office, at the manager's desk there are 2 wooden cubes to show the date of month, every day the manager sets the cubes ...
6
votes
7answers
4k views
If the second hand goes backwards, starting from 12:00, how long does it take to meet with the minute hand?
If the second hand of a clock goes backwards, starting from 12:00, how long does it take until it meets with the minute hand (which is going forwards)?
0
votes
2answers
631 views
Witches' Coffee [closed]
Two witches make a nightly visit to an all-night coffee shop. Each arrives at a random time between 0:00 and 1:00. Each one of them stays for exactly 30 minutes. On any one given night, what is the ...
3
votes
1answer
269 views
Infinite dials to reset ever?
I have an infinite number of dials with red needles that rotate $n\in\mathbb{Z^+}$ times every second. They all start pointing North.
Will they simultaneously all point North ever again?
6
votes
2answers
1k views
What's Bob's age again?
I created this problem myself, but I did have inspiration.
Today is a special day, I'm moving out of my parent's house. My father comes to me and says "Wow, you're half my age. On the day we moved ...
-1
votes
1answer
156 views
When was Sia born? [closed]
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
4
votes
3answers
256 views
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....
16
votes
5answers
943 views
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 ...
54
votes
12answers
12k views
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?
10
votes
6answers
844 views
Short Puzzle: Graphic Painting
The artist in the market is giving this painting for free (the last one on his rack). I asked him if I can take it but he replied "Why should I give it to you?" The frame could be useful but I dont ...
4
votes
5answers
452 views
Time-Motion puzzle
Time and Motion studies are well established.
Here is an easy question:
It takes 8 men 6 months to build 2 houses at a cost of $50,000.
It takes 10 men 5 months to build 3 houses at a cost of ...
23
votes
3answers
2k views
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.
...
11
votes
4answers
1k views
Mirrored clocks
Triangulating for the simplest puzzle that is still at least somewhat interesting to solve..
On the left side wall in this picture, we have two particular clocks:
1: an analog clock with identical ...
4
votes
2answers
873 views
What timezone am I?
It was 17:52 in the evening and I couldn’t wait for my class to finish. Only 8 more minutes… I really hate night school!
I sat there pondering the stuff on the blackboard and wondering why he wrote it ...
4
votes
2answers
262 views
Switching the clock
"Observe the time, would you, Watson, old chap?"
I did as instructed and glanced at the large grandfather clock standing in the corner. "Just a little after 4.42, Holmes."
He nodded, "So when the ...
1
vote
2answers
272 views
What are the chances on watching the clock? [closed]
This is a relatively straightforward little puzzle, but the answers are somewhat unintuitive or can prompt a new perspective. It might be an interesting little puzzle for a probability teaching ...
-8
votes
5answers
513 views
A cowboy rodeo riddle [closed]
First, the cowboy went to the rodeo on Monday.
Three days later, he went back home on Friday.
Can you solve it?
17
votes
14answers
11k views
My birthday is uncommon
I was born 1 day after my sibling. Yesterday was my sibling's birthday but today is not my birthday.
When is my birthday?
30
votes
11answers
13k views
Born on the same day, but one is two years older
Two people were born on the same day, same year, and share the same birthday.
One is 2 years old, the other is only a few days old.
What's going on here?
9
votes
2answers
289 views
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
7
votes
2answers
353 views
How many dates are ambiguous across the Atlantic?
The Day/Month/Year date system commonly used in Britain (and much of Europe?) and the Month/Day/Year system commonly used in the US can lead to confusion when, for example, we write 9/3/2018 for the ...
23
votes
1answer
1k views
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 ...
10
votes
4answers
1k views
How to rephrase this puzzle about a meditating monk and incense
Here's a math-flavored puzzle I found on Andrej Cherkaev's website that I like to give to my undergraduate math students. I've paraphrased it to try to make it clearer:
A monk was instructed by his ...
3
votes
5answers
590 views
Curiosity of February 5$^{th}$
Some people write February 5$^{th}$ using the md format, as $2.5$ or alternatively as $2/5$.
Note that $2.5 \times \frac25 = 1$.
Is there any other date satisfying $a.b \times \frac{a}{b} = 1$?
...
9
votes
2answers
508 views
A Final Twins Puzzle: Twelve Days Difference?
Inspired by @athin's One More Twin Puzzle: Four Days Difference?
After reading @athin's question, I was inspired to ask my own puzzle club about their birthdays. One of the members, Ethan, surprised ...
