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Primary 5 question exposes stress that singapore students face

winnipegjets

Alfrescian (Inf)
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Solved the question in a couple of minutes.

The wording and grammar are atrocious. I had to use more logic to understand what the examiner is asking, than to solve the problem once I understood the question.:rolleyes:


We should have a national discussion on the standard of English taught in sinkapore schools. Blame the Ah Nehs again? They become teachers and import the Indian English standard?
 

Asterix

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MOE don't import native English speakers from the British Isles anymore? What a tragedy!

[video=youtube;bhR1nJ1oY9M]https://www.youtube.com/watch?v=bhR1nJ1oY9M[/video]
 

sirus

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How to solve Albert, Bernard and Cheryl's birthday maths problem
Alex Bellos
Thanks everyone for trying the puzzle and showing your workings.

Here’s mine:

Remember, Albert is told either May, June, July or August.

Bernard is told either 14, 15, 16, 17, 18 or 19

Let’s go through it line by line.

Albert: I don’t know when Cheryl’s birthday is, but I know that Bernard doesn’t know too.

All Albert knows is the month, and every month has more than one possible date, so of course he doesn’t know when her birthday is. The first part of the sentence is redundant.

The only way that Bernard could know the date with a single number, however, would be if Cheryl had told him 18 or 19, since of the ten date options only these numbers appear once, as May 19 and June 18.

For Albert to know that Bernard does not know, Albert must therefore have been told July or August, since this rules out Bernard being told 18 or 19.

Line 2) Bernard: At first I don’t know when Cheryl’s birthday is, but now I know.

Bernard has deduced that Albert has either August or July. If he knows the full date, he must have been told 15, 16 or 17, since if he had been told 14 he would be none the wiser about whether the month was August or July. Each of 15, 16 and 17 only refers to one specific month, but 14 could be either month.

Line 3) Albert: Then I also know when Cheryl’s birthday is.

Albert has therefore deduced that the possible dates are July 16, Aug 15 and Aug 17. For him to now know, he must have been told July. Since if he had been told August, he would not know which date for certain is the birthday.

The answer, therefore is July 16.

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

https://www.youtube.com/watch?v=fSMvPQ2wvW0
 

zhihau

Super Moderator
SuperMod
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For Albert to know that Bernard does not know, Albert must therefore have been told July or August, since this rules out Bernard being told 18 or 19.

It's plain fallacy at play here.
1. Albert has no clue which day was told to Bernard and he assumes Bernard don't know.
2. There's no reason why Cheryl cannot tell Bernard the day of month she is born as 18 or 19.
3. When you rule out the 18th and 19th day of the month, you eliminate 2 dates specifically: 19th May & 18th June only. You can't write off 15th May, 16th May and 17th June as these are still possible dates.
Hence, we can see that Albert is a Dua Pao Xian.
 

Semaj2357

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No...there is 1 Cheryl in Mindef and all the JLB occifers want to know her birthdate....

amongst the low / high tech farmers in mindef, there must be a smart one with basic instinct to want to do something else - apart from just wanting to know her birthdate. hopefully, one fella from the "gunners" :rolleyes:
 

sirus

Alfrescian (Inf)
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It's plain fallacy at play here.
1. Albert has no clue which day was told to Bernard and he assumes Bernard don't know.
2. There's no reason why Cheryl cannot tell Bernard the day of month she is born as 18 or 19.
3. When you rule out the 18th and 19th day of the month, you eliminate 2 dates specifically: 19th May & 18th June only. You can't write off 15th May, 16th May and 17th June as these are still possible dates.
Hence, we can see that Albert is a Dua Pao Xian.

Next more interesting question would be who gets to bonk Cheryl?
 

SgGoneWrong

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Next more interesting question would be who gets to bonk Cheryl?

Neither. Cheryl got bonked by someone else :biggrin:

Solution:
Neither Albert nor Bernard got to up Cheryl even if they got her birthdate right and bought her expensive gifts. Like a typical sinkie spg, Cheryl got bonked by an ang moh tua kee who did not have to guess birthdate and Cheryl had to suck up to him to please him instead of her playing hard to get like how she would be with the 2 gong sinkies.
 

yellowarse

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It's plain fallacy at play here.

We have to assume that everyone is telling the truth. If everyone is lying, then there's no point in setting the question. (Unless it's a 'guess the liar' kind of question.)

All 3 statements must be taken in sequence​:

1. Albert has no clue which day was told to Bernard and he assumes Bernard don't know.

He didn't assume. He knew for sure. How come? It must be he was told by Cheryl that the month was either July or August, where the dates 18th or 19th could be excluded. That's why he knew for sure. (At this juncture only Albert knew the exact month; the rest of us only know it's either Jul or Aug.)

2. There's no reason why Cheryl cannot tell Bernard the day of month she is born as 18 or 19.

There is a reason: from Albert's POV, if Cheryl had told Albert it's July or August, it effectively ruled out 18 or 19 for Bernard. That's why Albert was very sure Bernard didn't know the month (see above). Bernard now deduces from Albert's 1st statement that the month is Jul or Aug, the way we 'outsiders' also deduced.

3. When you rule out the 18th and 19th day of the month, you eliminate 2 dates specifically: 19th May & 18th June only. You can't write off 15th May, 16th May and 17th June as these are still possible dates.

You can, from Bernard's statement. Bernard now knows that Albert must have been told by Cheryl that the month is July or August (see my explanation above). Bernard also knows the exact day.

What is this day that was told to him by Cheryl? If it's 14, then Bernard would be none the wiser, since the b'day could then be 14 Jul or 14 Aug. But Bernard now knows the exact birthdate. Therefore 14 is out.

That means Cheryl must have mentioned 15, 16, or 17. (Remember, at this stage only Bernard knows the exact day; the rest of us can only narrow it down to 15, 16 or 17.)

Albert's 2nd statement: Albert now knows the answer!

Why is Albert so smart? At this juncture outsiders only know it as 15, 16 or 17. Albert could only know the answer because the month that Cheryl mentioned must have been July. If Cheryl had said Aug to Albert, Albert still couldn't tell if it's 15 Aug or 17 Aug. But Albert now knows for sure. Therefore Aug is out.

Which leaves Jul 16 (we & Albert have already eliminated 14 above).
 
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zhihau

Super Moderator
SuperMod
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We have to assume that everyone is telling the truth. If everyone is lying, then there's no point in setting the question.

You're going in circular logic.
1. You started by assuming Cheryl telling Albert either Jul or Aug.
2. Cheryl can tell Albert any month & and tell Bernard any days between 14 to 17 and Albert's opening statement stand true.
3. There is no reason why Cheryl can't tell Bernard 18 or 19 as his statement concludes that he was clueless before the day was revealed and he knows after the day was revealed by Cheryl to him.
4. Since Bernard knows the birthdate as revealed by Cheryl, there's no reason why he wouldn't share it with Albert, hence Albert's concluding statement is that he also knows.
5. This can be supplemented by the context of the question where both Albert and Bernard are friends and they just got to know Cheryl.
6. This question aims to underscore the fact it's always "bros before holes" :biggrin::biggrin::biggrin:
7. 3 statements running in sequence and all stand true with none of them lying.
8. The answer could well be 18th June because Geminis have this weird trait of wanting to tell and not telling all at the same time.

:p:p:p
 
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looneytan

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Next more interesting question would be who gets to bonk Cheryl?
I have a feeling Cheryl looks like this !

np_20141025_huihui_651477.jpg


:eek::eek::eek:
 
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