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OK - this has me flummoxed:
A woman has a clock that strikes the number of hours every hour (e.g. it strikes four times at four o'clock). It also strikes once every half hour.
She goes into her house and as she opens the front door she hears the clock strike once.
Half an hour later it strikes again.
Half an hour later it strikes again.
Half an hour later it strikes again.
Half an hour later, just as she is going out of the door, she hears it strike once again.
What time was it as she entered the house and what time was it as she left again? (the clock is working correctly)
last stroke of 12
12.30
1
1.30
1st stroke of 2 (as door is shutting) ?
Given that that is probably the answer, what branch of maths is that?
12:30 am and 1:30am.... The day the clocks go back
More importantly, where is she going at 1:30am?
A clock? How quaint.
Answers above all assume a loaded question.
As a straight question it's unanswerable.
^ I'm glad you've said that as I don't think there is an answer. Will report back when we get the teacher's input
Maths?
2 hours have passed as measured by 5 events over 4 intervals, but given that you know only that the clock has struck, and not the number of times during the mid-intervals. It could be any period which starts on the half-hour and ends two hours later on the half hour.
What time was it as she entered the house and what time was it as she left again
It's time to get a chuffing clock that doesn't chuffing chime every chuffing half an hour!
what branch of maths is that?
logic.
So this woman has a clock in her house, which she has heard chime five times in the past two hours, but she still needs us to tell her what time it is??
She must work in management.
It's not logic. It's a smart-arsed question. It's likely to be muddy arsed guy's solution but that depends on you thinking of that particular situation and knowing about when the clocks go back (which 10 year olds might not). So it's not logic because you have to guess this and you aren't given it.
Other possibility:
She lives on a house boat/in a motor home which is near a time zone boundary, and the clock is a smart one that updates its time zone via GPS. The mobile house crosses the time zone boundary westwards between 1 o'clock and 2 o'clock.
Its not muddys answer, I'd bet its this as posted above -
last stroke of 12
12.30
1
1.30
1st stroke of 2 (as door is shutting) ?
Read the question, it says 'She goes into her house and as she opens the front door she [b]hears[/b] the clock strike once'
Not "the clock strikes once", but she [I]hears[/I] it strike once. Same for when she's leaving.
Logic.
Wouldn't she have to put the clock back? I think Scaredypants has it.
If it's a 24h clock; she enters at 12am, leaves at 2am
Wouldn't she have to put the clock back?
Not if it does it automatically. Could be electronic.
Often the people who set these questions have a particular answer in mind but aren't aware there are other valid answers, btw.
Not if it does it automatically. Could be electronic.
Not seen an electronic striking clock. Curious turn of phrase for one too, chime would be more typical
(I have no idea btw, just fun drawing this out :-D)
Not seen an electronic striking clock
It says 'the clock strikes'.
But since we are on this path.. another possibility:
The clock itself has a very quiet bell that cannot be heard from the front door. However it's mounted on a rotating arm that takes half an hour to complete a revolution. At one point on the clock's circuit is a bell which the clock bumps or strikes each revolution. This bell is much louder and is the one she hears.
Anyway, ask the "maths" teacher for their working.
I also have a question...
If a train from Somerset leaves at 1200 travelling South, and a train from Reading leaves at 12:15 travelling Northwest, then at what time will my father who left for a packet of cigarettes 25 years ago come back?
So it could be any time on the hour or half hour if the open/closing the door while chimes are starting/ending premise applies.
Is the clock on a treadmill ?
It's a sort of trick question - I don't think these do anything for giving children confidence in their maths ability.
OK, the rather annoying answer is:
She arrived on the last stroke of 12 o'clock and left on the first stroke of 2 o'clock.
Scaredypants has it
But I entirely agree with Prezet
It also strikes once every half hour.
Is it a train driver's clock?
So it could be any time on the hour or half hour if the open/closing the door while chimes are starting/ending premise applies.
Nope, the only way it can chime once three times in a row is around 1 'o' clock (12:30, 1:00 and 13:30). Once you've established that then it's clear she must have missed the other chimes for 12:00 and 02:00.
Where does it say it strikes *once* three times in a row 🙂
I think you should have told your kid about Schrodinger and his cat.
If nobody heard the clock strike then did the clock strike or not?
She arrived on the last stroke of 12 o'clock and left on the first stroke of 2 o'clock.
Rubbish! As has been pointed out, the question doesn't even specify how many times the clock struck the 2nd, 3rd and 4th time. It's a dreadful question and I'd be pointing that out to the teacher. It's like one of those awful riddles that has an improbable and convoluted answer (or several!); it teaches you how to think laterally but I'm not sure it has a place in maths teaching which is about rules and patterns.
The only "logic" I can see here is in recognising absolutes.
The only time it strikes once three times in succession is at 1am and the two adjacent half hours. That's a pretty straight-forward logic puzzle for a 10-year old I'd have said. The rest of it isn't logic, it's lateral thinking.
In fact, you know what it needs? Splitting in half.
Question 1.
The clock strikes once.
Half an hour later it strikes once.
Half an hour later it strikes once.
What time is it?
Question 2.
The OP's question as presented (only with 'once' explicitly stated each time).
[i]Then [/i]it's a logic puzzle, rather than what it is currently which is something dreamt up by a smartarse purely to make themselves feel superior to prepubescents.
They've used the word "again" to describe the 2nd -4th strike. So you look at how many strikes were described for the first strike to know how many strikes in 2nd-4th strike.
They've used the word "again" to describe the 2nd -4th strike.
I'm certain that's the intention, but it's badly worded and open to misinterpretation.
It's the sort of thing that crops up as an image on Facebook - "80% OF PEOPPLE WILL GET THIS WRONG!!1!" sort of affair - and sparks a row running to tens of thousands of posts precisely because it's vague (probably deliberately to attract clickbait followers).
Definitely could be worded better but we don't know how much of that is down to the teacher, where the teacher copied it from or the OPs paraphrasing.
No paraphrasing - straight off the question paper
The clock strikes once
Half an hour later it strikes once
Risking making a fool of myself while trying to sound clever...
Won't the 12th chime of 12:00 be at 12:00:12? [u]One hour[/u] later means hearing the 2nd chime of 14:00 at 14:00:02 (with another 10 seconds until an hour has passed at 14:00:12)
She could have entered the house at 1am after a heavy night and, being blind drunk, fell straight asleep for 12 hours and then woke up at 12am just before the next set of chimes?
Or she could have entered her extremely large house at 1am and then went upstairs to go to sleep in a back bedroom that was a long way from the chiming clock, and only came downstairs again at 12am just before the next set of chimes.
Not many 'striking' clocks adjust themselves for daylight savings. Chiming maybe, but not striking.
If a daylight saving time adjusting striker appears in the answer I would want to know the model before accepting that was the answer.
Not many 'striking' clocks adjust themselves for daylight savings
Not many clocks strike once on each half hour either (usually quarter) but that doesn't actually prevent that being a *possible* answer.
The question is stupid, as Cougar says the middle bit is fine, but all the guff about coming in at the end of 12 and leaving halfway through 2 is bullsh*t. She must have the fastest shutting door, that is also amazingly soundproofed to not hear the 2nd chime at 2 o'clock.
It's the type of question that will put kids off maths and does no one any favours. We should be giving them confidence, while challenging their abilities, not trying to knock them down.
Not many clocks strike once on each half hour either (usually quarter) but that doesn't actually prevent that being a *possible* answer.
I hadn't realised that, thanks.
It's not a maths question. No mathematical calculations are required to get the answer, e.g. no addition, no subtraction, no division or no multiplication.
It could have some merit in computer programming. You could solve it with logic (AND/OR/IF etc) either. E.g if clock sounding when entering the house, ignore it and wait for ~30 mins. Note the number of chimes, wait ~30 mins again. If number of chimes noted the 1st and 2nd times are 1 then.....etc
I remember doing some AND/OR logic at school, probably in maths. However the beginning and end hamper this and there are probably much better questions for pure logic
With absolute logic:
If the scenario is that she heard a chime when she walked in the door she [b]couldn't[/b] have heard another chime half an hour later (note: not 'about' half an hour later) - for the clock to chime 12 times it must have taken a while and thus the time difference could only have been something like 29 minutes and 30 seconds, not the definitive 30 minutes stated in the question.
So its unsolvable.
I claim my chocolate digestive.
If we're going with pure logic....
She goes into her house and as she opens the front door she hears the clock strike once.
I see the steps implied as
She's goes into her house. She is now within the house.
She opens the front door.
EDIT: There is a possible explanation. She entered the house by the back door then for some reason walked through the house and opened the front door. But then that messes with the door opening/closing cutting off the clock chimes..
EDIT2 Unless the back door cuts off the chimes...
It could have some merit in computer programming.
Not a bad exercise in deductive reasoning, which is useful for debugging things. The usual conversation goes:
Them: We've got this error message
Me: That's caused by X
Them: But we've checked X and it's fine. This is impossible.
Me: Well it must not be, because you had the error message.
Them: But we've checked it
Me: Well, under what circumstances could X appear to be fine, but not actually be? Something else is indirectly causing X to not be fine.
Them: <go away to think about it>
Them: Yeah you were right, we thought about it and it was something that made X look ok but it wasn't.
There was no clock. Woman has tinnitus.