Are you smarter than Singaporean kids?

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lnc

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This question was part of a Singapore and Asian Schools Math Olympiad test paper.  For all the brainiacs here, see if you can solve this. :)

Can you solve the maths question for Singapore schoolkids

be00992c-012d-4216-9e7a-2751a79c75c4-620x372.jpeg


To clear up any ambiguity, Cheryl tells Albert the month in which her birthday falls, and she tells Bernard the day?s number.

In other words, Albert is told either May, June, July or August. Bernard is told either 14, 15, 16, 17, 18 or 19.
Click to expand...


Here's link to the answer.
 
lnc said:
This question was part of a Singapore and Asian Schools Math Olympiad test paper.  For all the brainiacs here, see if you can solve this. :)

Can you solve the maths question for Singapore schoolkids

be00992c-012d-4216-9e7a-2751a79c75c4-620x372.jpeg


To clear up any ambiguity, Cheryl tells Albert the month in which her birthday falls, and she tells Bernard the day?s number.

In other words, Albert is told either May, June, July or August. Bernard is told either 14, 15, 16, 17, 18 or 19.
Click to expand...


Here's link to the answer.
Click to expand...
 
Try this one, if you solved the birthdays you should find it easy:

Two friends meet after long break.
After a short chat they start talking about kids.

Adam: So do you have kids?
Joe: Yes I do!
Adam: How many and what's their age?
Joe: Well, if you multiply their ages you'll get 36. And the sum of their ages equals the sum of windows in this building. This should be enough to answer your question.
Adam: I'm afraid I'm still missing something.
Joe: Oh, I forgot! The oldest one has blue eyes!
Adam: Thanks mate, everything's clear now!

How many kids has Joe, and how old are they?
 
Let me guess. The answer should be Aug 17.

From Albert's 1st sentence,
1. Cheryl's birthday should not be 18, 19. If so, Bernard knows Cheryl's birthday at once.
2. Cheryl's birthday should not be in June. If so, Albert himself knows at once.
3. From Bernard's sentence, Bernard knows at once. Then the number should be 17 since only one 17 is in the list now.

 
The California Court Company said:
Try this one, if you solved the birthdays you should find it easy:

Two friends meet after long break.
After a short chat they start talking about kids.

Adam: So do you have kids?
Joe: Yes I do!
Adam: How many and what's their age?
Joe: Well, if you multiply their ages you'll get 36. And the sum of their ages equals the sum of windows in this building. This should be enough to answer your question.
Adam: I'm afraid I'm still missing something.
Joe: Oh, I forgot! The oldest one has blue eyes!
Adam: Thanks mate, everything's clear now!

How many kids has Joe, and how old are they?
Click to expand...

Since we don't know the number of windows, many possible answers: could be two kids (9 and 4 or 18 and 2), three kids (9 and 4 and 1).  Or you can even have 6 and 6 (Looks like the blue eyes is meant to disqualify twins but kids can be born 10 or 11 months apart).. etc
 
process by elimination people.

For the month Albert is told, he is sure there is zero chance the day given to Bernard, Bernard would know the answer. May and June are out because if Albert is given May, he cannot say for sure because Bernard could've been given 19. Same for June 18.

So you cross off two months.

So Bernard knows it is in either July or August. If Bernard's day is 14, he would not know it is July or August. So you cross off day 14 and 3 dates left, 1 in July and 2 in August.

For Albert to know the exact date, it must be in July because if he is told August he would not know which date.



 
kiki said:
Let me guess. The answer should be Aug 17.

From Albert's 1st sentence,
1. Cheryl's birthday should not be 18, 19. If so, Bernard knows Cheryl's birthday at once.
2. Cheryl's birthday should not be in June. If so, Albert himself knows at once.
3. From Bernard's sentence, Bernard knows at once. Then the number should be 17 since only one 17 is in the list now.
Click to expand...

Let me re-write again.

From Albert's sentence, "I don't know when Cheryl's birthday is, but I know that Bernard does not know too."
1.
Since 18 and 19 appear once, these two days should be eliminated or Bernard will know.
Now the list is:

May 15, May16
June17
July14, July16
August14, August15, August17

2.
The month can not be June or Albert would know by himself.
Now the list is:

May 15, May 16
July 14, July 16
August 14, August 15, August 17

From Bernard's sentence, "At first I don't know when Cheryl's birthday is, but I know now"
The answer is 17 since only 17 appears once. If not 17, Bernard will not know now.
 
did you look at the answer?  aug 17 is incorrect.  :'(

anyway, their explanation on step #2 does NOT make sense. 
 
Let's see if you can figure out my math problem:

Q. If I have 10 ice cubes and you have 11 apples, how many pancakes will fit on the roof?
 
step 1 you need to cross off May and June. Albert knows for a certainty that Bernard does not know. If May is given to Albert, Albert will not know for sure if Bernard is given 19 or not. In other words, the month that is given to Albert, must have days that show up in other months so regardless which day given to Bernard in that month, Bernard cannot tell which month.

With July and August left, Bernard must be given 15, 16 or 17 so he can know for certain. In other words, out of the 5 left, two days have the same month so if Bernard is given that day, he cannot tell.

With 1 date left in July and 2 dates left in August, only way for Albert to know for sure is he is given July. In other words, if Albert is given August, he cannot tell which day.



kiki said:
kiki said:
Let me guess. The answer should be Aug 17.

From Albert's 1st sentence,
1. Cheryl's birthday should not be 18, 19. If so, Bernard knows Cheryl's birthday at once.
2. Cheryl's birthday should not be in June. If so, Albert himself knows at once.
3. From Bernard's sentence, Bernard knows at once. Then the number should be 17 since only one 17 is in the list now.
Click to expand...

Let me re-write again.

From Albert's sentence, "I don't know when Cheryl's birthday is, but I know that Bernard does not know too."
1.
Since 18 and 19 appear once, these two days should be eliminated or Bernard will know.
Now the list is:

May 15, May16
June17
July14, July16
August14, August15, August17

2.
The month can not be June or Albert would know by himself.
Now the list is:

May 15, May 16
July 14, July 16
August 14, August 15, August 17

From Bernard's sentence, "At first I don't know when Cheryl's birthday is, but I know now"
The answer is 17 since only 17 appears once. If not 17, Bernard will not know now.
Click to expand...
 
The California Court Company said:
Try this one, if you solved the birthdays you should find it easy:

Two friends meet after long break.
After a short chat they start talking about kids.

Adam: So do you have kids?
Joe: Yes I do!
Adam: How many and what's their age?
Joe: Well, if you multiply their ages you'll get 36. And the sum of their ages equals the sum of windows in this building. This should be enough to answer your question.
Adam: I'm afraid I'm still missing something.
Joe: Oh, I forgot! The oldest one has blue eyes!
Adam: Thanks mate, everything's clear now!

How many kids has Joe, and how old are they?
Click to expand...

2 2 3 3
2 3 6
2 18
3 3 4
3 12
4 9
6 6

sum of all windows - guessing typical square or rectangle building will have even number of windows which leaves:
2 2 3 3
2 18
6 6

oldest one has blue eyes - again assuming twins are identical which leaves:
2 18

 
lnc said:
This question was part of a Singapore and Asian Schools Math Olympiad test paper.  For all the brainiacs here, see if you can solve this. :)

Can you solve the maths question for Singapore schoolkids

be00992c-012d-4216-9e7a-2751a79c75c4-620x372.jpeg


To clear up any ambiguity, Cheryl tells Albert the month in which her birthday falls, and she tells Bernard the day?s number.

In other words, Albert is told either May, June, July or August. Bernard is told either 14, 15, 16, 17, 18 or 19.
Click to expand...


Here's link to the answer.
Click to expand...

Albert, Bernard... listen. Cheryl is just playing "hard to get". She is not worth your time. And if she is this coy when asked for her birthday, just imagine the greater confusion if you boys asked for her phone number!
 
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