Can you solve this maths problem from Singapore?

Muir · 15-04-2015 10:05PM

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!

15-04-2015 10:06PM

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 · 15-04-2015 10:28PM

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

Liminz · 15-04-2015 10:44PM

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 · 15-04-2015 10:46PM

Banjo String wrote: »

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

15+15

It doesn't say you must use all spaces

Muir · 15-04-2015 10:52PM

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

Liminz · 15-04-2015 10:53PM

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 · 15-04-2015 10:54PM

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 · 15-04-2015 10:54PM

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 · 15-04-2015 10:56PM

Liminz wrote: »

-1 isn't an option.

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

Muir · 15-04-2015 10:57PM

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 · 15-04-2015 11:14PM

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 · 15-04-2015 11:23PM

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 · 16-04-2015 12:50AM

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 · 16-04-2015 01:00AM

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 · 16-04-2015 01:02AM

Junkyard Cat wrote: »

Well done on the googling and lack of spoilers lads.

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

Liminz · 16-04-2015 06:49AM

Muir wrote: »

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

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

Liminz · 16-04-2015 06:50AM

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 · 16-04-2015 08:15AM

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 · 16-04-2015 08:29AM

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.

Plazaman · 16-04-2015 08:30AM

Said I to meself, "Self, 10 year old Sinagaporian kids can solve this, dust off the brainpan and solve it FFS". Then I couldn't

However upon consulting with Professor Google, I find out that this was a question in a maths olympic type competition for 15/16 year olds nerds so I felt a little bit better and went straight back to looking at cats doing funny things on YouTube and relishing the fact that Cheryl has no friends.

Turtwig · 16-04-2015 09:06PM

Plazaman wrote: »

Said I to meself, "Self, 10 year old Sinagaporian kids can solve this, dust off the brainpan and solve it FFS". Then I couldn't

However upon consulting with Professor Google, I find out that this was a question in a maths olympic type competition for 15/16 year olds nerds so I felt a little bit better and went straight back to looking at cats doing funny things on YouTube and relishing the fact that Cheryl has no friends.

Even if it was for 10 year olds you shouldn't feel bad. This is something that always confuses me about maths in particular. (Even though this is isn't strictly a maths question.) If this was a music exam asking you to compose or play a precise piece and you'd never done music before you wouldn't feel one bit aggrieved. Yet, somehow, people think that maths - and in this case logic puzzles- are some unique innate ability that you either have or don't. The bottom line is that most people who solve it can do so because they've encountered stuff like this before on a regular enough basis to train their brain how to do so. When it comes to music, art or sport. People are generally accepting of this learning curve, yet when it comes to maths. . .

btw, not saying you are one of these people.

Just using your exasperation as an opportunity to semi vent my confusion.

Meath Centre Forward · 16-04-2015 09:53PM

I got July 16th on the basis that...

If Albert got May or June, he could not say Bernard does not know. If Bernard got 18 or 19 he would know the whole date. Therefore Albert has July or August.

Following on from this statement, Bernard now also knows Albert has July or August. He also says he knows the date meaning he does not have a 14 as that is common to both July or August.

Following on from this statement Albert says he's knows meaning he does not have August as there are 2 possible dates there which Bernard could have.

We are left with JUly 16th.

Knasher · 16-04-2015 09:59PM

Muir wrote: »

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

It also doesn't say that you can't set the piece of paper on fire for being deliberately misleading.

So that is my solution.

Wacker The Attacker · 16-04-2015 11:01PM

I'm more curious about this threesome.

Wacker The Attacker · 16-04-2015 11:03PM

These kids clearly need more booze and pussy.

Panthro · 16-04-2015 11:35PM

the_monkey wrote: »

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

Thank god.
I thought I was the only one who came up with that.
Well, now ive confirmstion that i was sheeeeeite at maths!

Maximus Alexander · 17-04-2015 09:24AM

I suspect any computer programmer would get this pretty easily. It's just straight logic - which is as much a learned skill as anything else. I wouldn't feel bad if you didn't get it, you're probably not solving logic puzzles on a daily basis.

daheff · 17-04-2015 10:05AM

smash wrote: »

15+15

It doesn't say you must use all spaces

Liminz wrote: »

-1 isn't an option.

Muir wrote: »

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

Muir wrote: »

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

Liminz wrote: »

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

Its a poorly phrased question. I'd also suspect that the start of the exam paper says something about following the instructions given on the paper(ie dont do something thats not explicitly told) It doesn't say that you can only use the numbers provided. It just says Fill the boxes using the list of numbers given and that you can also repeat the numbers. Based off instructions given its impossible (as far as i can see). You arent given permission to put any mathematical operators into the box or leave a box blank(put in a 0) or to say 1 day=24 hours and add 5 +1 more hours =30 hours.

but on the basis of outside the box thinking (:eek:) then you could just as easily have 1+1+1+1+1+1+1+1+1+1 (ie 10) in each of the boxes -or any other version suggested above.

Knasher wrote: »

It also doesn't say that you can't set the piece of paper on fire for being deliberately misleading.

So that is my solution.

I like this solution...probably set fire to it while its nailed onto the person who wrote that question :cool:

Can you solve this maths problem from Singapore?

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