Can you solve this maths problem from Singapore?

CaliforniaDream

http://www.theguardian.com/science/alexs-adventures-in-numberland/2015/apr/13/can-you-solve-the-singapore-primary-maths-question-that-went-viral

This maths problem is on a test in a school in Singapore. It's intended for 15 year olds.
Can you figure it out without cheating? It took me about 20 mins but I got it. You just need to figure out where to start then it's easy.

MonkeyTennis

Yep.. Cheryl is an a$$hole.

Aint Eazy Being Cheezy

July 16

CaliforniaDream

MonkeyTennis wrote: »

Yep.. Cheryl is an a$$hole.

See I'm female so I empathised with Cheryl for 20 mins before I got that answer.

Muir

July 16th

seventeen sheep

Why is Cheryl being such a tool? Either tell them or don't tell them. Why do they even care enough to go to the effort of trying to work it out? Gobsh1tes the three of them.

Fr_Dougal

CaliforniaDream wrote: »

http://www.theguardian.com/science/alexs-adventures-in-numberland/2015/apr/13/can-you-solve-the-singapore-primary-maths-question-that-went-viral

This maths problem is on a test in a school in Singapore. It's intended for 15 year olds.
Can you figure it out without cheating? It took me about 20 mins but I got it. You just need to figure out where to start then it's easy.

What about Kony? He hasn't gone away you know.

Junkyard Tom

The Cunning Linguist wrote: »

July 16

Muir wrote: »

July 16th

Well done on the googling and lack of spoilers lads.

Sheep Lover

Next Tuesday.

Muir

Junkyard Cat wrote: »

Well done on the googling and lack of spoilers lads.

I worked it out when I first seen it a couple of days ago, and I didn't see a need for spoilers because in any other discussion on it pretty much every date has been guessed and debated. Thought the same would probably happen here. Didn't post up a solution yet because I thought that was more of a spoiler.

Mister Vain

Me is stupider than a Singaporean ten year old.

Turtwig

It's not a maths problem. It's a standard deductive logic puzzle. Anyone who's played professor layton will be very familiar with these.

I hate the way people are thinking they're beneath solving it. Most people who solved it or could understand the solution are able to do so because they've more familiarity with these types of problems than others do. Hell, any programmer worth their salt should be able to understand the solution.

Rough Sleeper

It looks gold and white to me.

Turtyturd

Mister Vain wrote: »

Me is stupider than a Singaporean ten year old.

Thats unpossible.

Donnielighto

Simple enough when you know the approach, which is why it shouldnt be assumed that singaporeans are geniouses wrt maths but that they are taught in a more real world manner. Although this is early math (read logic)

Junkyard Tom

Turtwig wrote: »

It's not a maths problem.

When I was reading it I was thinking 'this isn't maths' - that confusion and the very idea that it was a maths problem made me averse to meaningfully tackling the question.

I think I have a touch of pseudo-dyscalculia.

murpho999

Junkyard Cat wrote: »

Well done on the googling and lack of spoilers lads.

How do you know you didn't work it out and why would you need spoilers as they were asked a question?

Don't get spoilers at all as I think people just have to look at them.

smash

Mister Vain wrote: »

Me is stupider than a Singaporean ten year old.

Don't beat yourself up...

It now appears that the question was not intended for year 5 primary schoolkids but in fact for 14/15-year olds. According to Singapore news agency Mothership.sg the question was part of a Singapore and Asian Schools Math Olympiad test paper, which is aimed at the best 40 per cent of students.

You're only not smarter that 40% of Singaporean 14 year olds

if the house two doors to the left has a yellow roof and the house one door to the right has a blue door and *snore*

smash

bluewolf wrote: »

if the house two doors to the left has a yellow roof and the house one door to the right has a blue door and *snore*

Green!?

Vowel Movement

Will someone splain the answer. I can't work google:(

job seeker

CaliforniaDream wrote: »

http://www.theguardian.com/science/alexs-adventures-in-numberland/2015/apr/13/can-you-solve-the-singapore-primary-maths-question-that-went-viral

This maths problem is on a test in a school in Singapore. It's intended for 15 year olds.
Can you figure it out without cheating? It took me about 20 mins but I got it. You just need to figure out where to start then it's easy.

Thats nothing, can you solve this?

the_monkey

May 19, 19 is the only unique number ....

d2ww

A knows the Month, B knows the day.
1. If B does know, it can't be the 18th or 19th as they are unique. Therefore, it can't be June 17th as A would know.
2. with june 17th eliminated that leaves Aug 17th as unique which B realises.
3. So it's Aug 17th.

Or in others words, how did people get July 16th?

the_monkey

load of bollox, it's not a maths puzzle


its a tricky semantics load of shyte...

Liminz

Got it in 6 mins. Clever question. I'd imagine in exam settings though it could be more difficult given your mind would be checking the clock.

d2ww

the_monkey wrote: »

May 19, 19 is the only unique number ....

That doesn't tally with the first line "but I know that B does not know too"

Liminz

Vowel Movement wrote: »

Will someone splain the answer. I can't work google:(

after each statement look at it from both perspectives. rule out what both of them could not have been told, then you come to the only answer consistent with all statements.

Each party hears the previous statement and can deduce from that and rule out possibilities.

Liminz

the_monkey wrote: »

load of bollox, it's not a maths puzzle


its a tricky semantics load of shyte...

Semantics it certainly isn't , it's logic.

Muir

d2ww wrote: »

A knows the Month, B knows the day.
1. If B does know, it can't be the 18th or 19th as they are unique. Therefore, it can't be June 17th as A would know.
2. with june 17th eliminated that leaves Aug 17th as unique which B realises.
3. So it's Aug 17th.

Or in others words, how did people get July 16th?

I'll put my solution in spoilers

A states that B does not know. The only way A can know this is that A knows it is not May or June (the only two months with unique dates).

A making this statement means B know realises that May and June are ruled out, and B now knows the answer. This means it can't be either of the 14s because B couldn't know then.

Finally, A now knows. This means that it can't be August as there would still be two options remaining, so it's July 16th.

d2ww

Muir wrote: »

I'll put my solution in spoilers

A states that B does not know. The only way A can know this is that A knows it is not May or June (the only two months with unique dates).

A making this statement means B know realises that May and June are ruled out, and B now knows the answer. This means it can't be either of the 14s because B couldn't know then.

Finally, A now knows. This means that it can't be August as there would still be two options remaining, so it's July 16th.

Thanks, but my reading of the first line is that only the 18th and 19th are eliminated since B would know straight off. Also, it can't be June since A knowing that 18th and 19th are out, still doesn't know. So how did you eliminate May?

Muir

d2ww wrote: »

Thanks, but my reading of the first line is that only the 18th and 19th are eliminated since B would know straight off. Also, it can't be June since A knowing that 18th and 19th are out, still doesn't know. So how did you eliminate May?

They're eliminated because A knows B doesn't know. The only possible way A could know this is by knowing it isn't in May or June because A only knows the month. A knowing that it isn't May or June is the only reason A can say for sure that B definitely doesn't know what the date is. If Cheryl had told A it was May or June then A couldn't make that first statement.
Hope that makes sense, not easy to explain online!

d2ww

d2ww wrote: »

Thanks, but my reading of the first line is that only the 18th and 19th are eliminated since B would know straight off. Also, it can't be June since A knowing that 18th and 19th are out, still doesn't know. So how did you eliminate May?

http://www.theguardian.com/science/alexs-adventures-in-numberland/2015/apr/13/how-to-solve-albert-bernard-and-cheryls-birthday-maths-problem

Banjo String

This one had, and still has me puzzled.....

Liminz

Banjo String wrote: »

This one had, and still has me puzzled.....

You can't add three off numbers and get an even number. It has no solution.

smash

Banjo String wrote: »

This one had, and still has me puzzled.....

15+15

It doesn't say you must use all spaces

Muir

Also doesn't say you can't put multiple numbers in a space so:
(15-1) + 15 + 1 = 30

Liminz

Muir wrote: »

Also doesn't say you can't put multiple numbers in a space so:
(15-1) + 15 + 1 = 30

-1 isn't an option.

Banjo String

Muir wrote: »

Also doesn't say you can't put multiple numbers in a space so:
(15-1) + 15 + 1 = 30

Yep, just saw the solution.

My better half copped that in about 30secs too.

smash

Muir wrote: »

Also doesn't say you can't put multiple numbers in a space so:
(15-1) + 15 + 1 = 30

Sure you might as well start using decimal places if you're going to do that.

Muir

Liminz wrote: »

-1 isn't an option.

(3+7) + (3+7) + (3+7) = 30

Muir

smash wrote: »

Sure you might as well start using decimal places if you're going to do that.

Well it doesn't say you can't use decimals!

ressem

smash wrote: »

15+15

It doesn't say you must use all spaces

But it does say fill in the boxes.

I would have tried
() + 15 + 15
where () evaluates to 0. I don't think mucking around with intervals or exponentials would get anywhere. Nor adding in other maths operators.

Muir

Could also have 1 day + 3 hours + 3 hours = 30 hours
or 3(+3 +7) since it says "fill the boxes using" and the brackets could be included in that

Cee-Jay-Cee

I can't figure it out even knowing the answer.

Is it me or is it very badly written/explained in the original Question?

shruikan2553

Cee-Jay-Cee wrote: »

I can't figure it out even knowing the answer.

Is it me or is it very badly written/explained in the original Question?

I found it a bit difficult to understand too.

Maximus Alexander

Junkyard Cat wrote: »

Well done on the googling and lack of spoilers lads.

The Googling :rolleyes: It's a straightforward logic puzzle.

Liminz

Muir wrote: »

(3+7) + (3+7) + (3+7) = 30

Where does it say you can fill the box with a plus sign?

Liminz

Cee-Jay-Cee wrote: »

I can't figure it out even knowing the answer.

Is it me or is it very badly written/explained in the original Question?

It's explained perfectly well.

Banjo String

Liminz wrote: »

Where does it say you can fill the box with a plus sign?

It doesn't, it just says using the numbers supplied, and you can repeat the same numbers.

It doesn't say what you must do inside the brackets though.
There are loads of combinations so.

Dog of Tears

Cee-Jay-Cee wrote: »

I can't figure it out even knowing the answer.

Is it me or is it very badly written/explained in the original Question?

It's you.