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Wednesday, 15 April 2015

Can you solve this maths question?

This maths question has gone viral. It's reportedly a maths question for Singapore primary school kids. Anyone know the answer?

266 comments:

«Oldest   ‹Older   201 – 266 of 266
Dera said...

Tricky, but it's July 16th.

Anonymous said...

It
's May 19....@az

@PeterMusicNote said...

Answer: only Cheryl and God knows

Unknown said...

Will be back to read comments to get the answer.

What!

Adeyemi said...

Rubbish. This isn't maths, the teacher obviously is drunk.

Unknown said...

Clueless


JONRISA

Anonymous said...

july 16th

Anonymous said...

May 19

Anonymous said...

July 16th

Vidda said...

First we need to figure out if Albert knows the month or the day. If he knows the day, then there is no chance that Bernard knows the birthday, so it must be that Albert knows the month.

From the first statement, we know that Albert is sure that Bernard doesn't know the birthday, so May and June should be ruled out (the day 19 only appears in May and the day 18 only appears in June). In other words, if Albert had May or June, then he cannot be sure that Bernard doesn't know, since Bernard could have had 18 or 19.

Following that statement, Bernard knows that May and June are ruled out.

Then, Bernard is able to know which month it is. So it must be either July 16, August 15 and August 17 (not 14th as then he can't know).

Since Albert subsequently can also be sure of the date, he must know it's July. If it's August, he can't be sure as there is August 15 and 17.

So the answer is July 16.

Vidda said...

First we need to figure out if Albert knows the month or the day. If he knows the day, then there is no chance that Bernard knows the birthday, so it must be that Albert knows the month.

From the first statement, we know that Albert is sure that Bernard doesn't know the birthday, so May and June should be ruled out (the day 19 only appears in May and the day 18 only appears in June). In other words, if Albert had May or June, then he cannot be sure that Bernard doesn't know, since Bernard could have had 18 or 19.

Following that statement, Bernard knows that May and June are ruled out.

Then, Bernard is able to know which month it is. So it must be either July 16, August 15 and August 17 (not 14th as then he can't know).

Since Albert subsequently can also be sure of the date, he must know it's July. If it's August, he can't be sure as there is August 15 and 17.

So the answer is July 16.

Anonymous said...

The answer is July 16th...I saw this on BBC World last night and the mathematician got July 16th

Laurie said...

May 19

Timi Da Uyi said...

Copy copy Linda

Unknown said...

The answer is July 16th...I saw this on BBC World last night and the mathematician got July 16th

Unknown said...

LMAO! Pls linda tell us d answer

Laurie said...

Very easy, May 19

Anonymous said...

So this one looks like maths to you abi....
smh, na wa 4 u linda.....

Adeniran Opeyemi said...

First we need to figure out if Albert knows the month or the day. If he knows the day, then there is no chance that Bernard knows the birthday, so it must be that Albert knows the month.

From the first statement, we know that Albert is sure that Bernard doesn't know the birthday, so May and June should be ruled out (the day 19 only appears in May and the day 18 only appears in June). In other words, if Albert had May or June, then he cannot be sure that Bernard doesn't know, since Bernard could have had 18 or 19.

Following that statement, Bernard knows that May and June are ruled out.

Then, Bernard is able to know which month it is. So it must be either July 16, August 15 and August 17 (not 14th as then he can't know).

Since Albert subsequently can also be sure of the date, he must know it's July. If it's August, he can't be sure as there is August 15 and 17.

So the answer is July 16.

Anonymous said...

July 16

suqpy said...

Really...

Anonymous said...

JUly 16

Anonymous said...

July 16

BarnaStinson said...

It requires kind of a deductive reasoning technique. the answer is July 16.
For small kids tho... This is really quantitative reasoning.

Anonymous said...

July 16

Anonymous said...

July 16

Anonymous said...

linda wat's your own answer? mine is June 21

Unknown said...

The answer is July 16.

SOLUTION:

Out of the 10 dates, the day ranges from 14 to 19, with only 18 and 19 each occuring once. If the day of Cheryl's birthday is 18 or 19, then Bernard would have known when Cheryl's birthday is since Cheryl has told him the day of her birthday.

But why does Albert know that Bernard does not know?

If Cheryl has told Albert that her birth month is May or June, then it is possible that her birthday may be May 19 or June 18. This means that Bernard may know when Cheryl's birthday is. The fact that Albert knows that Bernard does not know means that Cheryl has told Albert that her birth month is either July or August.

Initially, Bernard does not know when Cheryl's birthday is, but how did he know after Albert has first spoken?

Out of the 5 remaining dates in July and August, the day ranges from 15 to 17, with only 14 occuring twice.

If Cheryl has told Bernard the day of her birthday is 14, then Bernard would not have known.

The fact that Bernard knows means the day of her birthday is not 14. so now we are left with 3 possible dates: July 16, August 15 and August 17.

After Bernard has spoken, Albert now knows when Cheryl's birthday is. If Cheryl has told Albert her birth month is August, then Albert would not have known because there are two possible dates in August.

Therefore, Cheryl's birthday is on July 16!

In actual fact, this shows that Cheryl is evil and absolutely no fun and Albert and Bernard need better freinds!

Unknown said...

June 18... there are only two dates that occurs only once (18 and 19). Since Albert's answer depends on Bernard's answer then for Bernard to be logically correct the dates must be unique and the month must have an 'either/or' probability.

Unknown said...

The answer is July 16.

SOLUTION:

Out of the 10 dates, the day ranges from 14 to 19, with only 18 and 19 each occuring once. If the day of Cheryl's birthday is 18 or 19, then Bernard would have known when Cheryl's birthday is since Cheryl has told him the day of her birthday.

But why does Albert know that Bernard does not know?

If Cheryl has told Albert that her birth month is May or June, then it is possible that her birthday may be May 19 or June 18. This means that Bernard may know when Cheryl's birthday is. The fact that Albert knows that Bernard does not know means that Cheryl has told Albert that her birth month is either July or August.

Initially, Bernard does not know when Cheryl's birthday is, but how did he know after Albert has first spoken?

Out of the 5 remaining dates in July and August, the day ranges from 15 to 17, with only 14 occuring twice.

If Cheryl has told Bernard the day of her birthday is 14, then Bernard would not have known.

The fact that Bernard knows means the day of her birthday is not 14. so now we are left with 3 possible dates: July 16, August 15 and August 17.

After Bernard has spoken, Albert now knows when Cheryl's birthday is. If Cheryl has told Albert her birth month is August, then Albert would not have known because there are two possible dates in August.

Therefore, Cheryl's birthday is on July 16!

In actual fact, this shows that Cheryl is evil and absolutely no fun and Albert and Bernard need better freinds!

Anonymous said...

AUGUST 19

Anonymous said...

SHE TOLD THEM THE MONTH AND DAY SEPARATELY REMEMBER?

Da Epic Pen said...

The problem can be solved using frequency of occurrence. Do you observe that the months of May, June, July and August appeared 3, 2, 2, 3 times respectively.
While the days 14, 15, 16, 17 all appeared twice except 18 & 19 which appeared once.
SOLUTION
Cheryl told Albert the month and Bernard the day. There is no clue given, thus we can only unravel the mystery birthday from the conversation.
Note: Albert used a code to tell Bernard the month of Cheryl's birthday, and Bernard vice-versa in revealing the day.
Albert: "I dont know when Cheryl's Birthday is, but I know that Bernard does not know TOO (two or 2).
The code is that the month of Cheryl's birthday appeared twice on the list of 10 possible dates. June and July appeared twice.

Bernard at the point is certain of the answer since he knows the day.
So he uses a code to reveal the day to Albert.
Bernard: "At FIRST (1st) I don't know when Cheryl's birthday is, ..."
The code is that the day appeared first time, or once. That leaves us with 19 and 18 for possible days and June and July for possible months.
But its only June that has 18.
So Cheryl's birthday is June 18.

Da Epic Pen said...

The problem can be solved using frequency of occurrence. Do you observe that the months of May, June, July and August appeared 3, 2, 2, 3 times respectively.
While the days 14, 15, 16, 17 all appeared twice except 18 & 19 which appeared once.
SOLUTION
Cheryl told Albert the month and Bernard the day. There is no clue given, thus we can only unravel the mystery birthday from the conversation.
Note: Albert used a code to tell Bernard the month of Cheryl's birthday, and Bernard vice-versa in revealing the day.
Albert: "I dont know when Cheryl's Birthday is, but I know that Bernard does not know TOO (two or 2).
The code is that the month of Cheryl's birthday appeared twice on the list of 10 possible dates. June and July appeared twice.

Bernard at the point is certain of the answer since he knows the day.
So he uses a code to reveal the day to Albert.
Bernard: "At FIRST (1st) I don't know when Cheryl's birthday is, ..."
The code is that the day appeared first time, or once. That leaves us with 19 and 18 for possible days and June and July for possible months.
But its only June that has 18.
So Cheryl's birthday is June 18.

Anonymous said...

August 17th

Anonymous said...

And a primary school student is expected to do all analysis. Oriegwu.

snick said...

This is mental reasoning and not math. That there are some numbers in the problem, doesn't make it math.... poor kids. Thanks to Ben Sleek and Ekene for the explanation because I was clueless.

Tolulope said...

july 16

Unknown said...

My dear I tire o

Unknown said...

Lol

Anonymous said...

More than half of the commenters here don't know the answer... Some didn't even try!... Yet they are quick to make noise about Okonjo Iweala and the Nigerian govt. Do you think the economy is run by 1+1? Or by constructing a big building and placing machineries and then you jubilate that job is available? It is a pity that you will be the first to point fingers at things that are bad. Okay defend your degrees... You can't! Talk less of taking a look at your CVs... Let me just stop here..if not, Aunt Linda will be tired of my epistle.

Unknown said...

July 14

Anonymous said...

D question no make sense, even d analysis of d answer isn't understandable. It is disastrous, confusing ,orubebesing, etc

Anonymous said...

The answer in TODAY!!!! NOW!!!, not yesterday or tomorrow ;)

Why in Sigapore in a narrative you dont say xyz just becAme friends not just become friends..



then it is what she mentioned "At first" Bernard says so .

otherwise the answer is : She wont tell them.

Unknown said...

No be small thing

Anonymous said...

July 16th

solitary said...

june17

Obi Wan said...

April 1

Anonymous said...

Abeg ee no make sense

Henry George Slim C said...

First we need to figure out if Albert knows the
month or the day. If he knows the day, then there
is no chance that Bernard knows the birthday, so
it must be that Albert knows the month.
From the first statement, we know that Albert is
sure that Bernard doesn’t know the birthday, so
May and June should be ruled out (the day 19 only
appears in May and the day 18 only appears in
June). In other words, if Albert had May or June,
then he cannot be sure that Bernard doesn’t know,
since Bernard could have had 18 or 19.
Following that statement, Bernard knows that May
and June are ruled out.
Then, Bernard is able to know which month it is.
So it must be either July 16, August 15 and August
17 (not 14th as then he can’t know).
Since Albert subsequently can also be sure of the
date, he must know it’s July. If it’s August, he can’t
be sure as there is August 15 and 17.
So the answer is July 16.

Unknown said...

Prove your answer with calculation. Smiles

Unknown said...

Pls proof the answer with calcu5

O.N. Progeny said...

Linda, u can find it by using determining the average of the dates the girl gave or the mode. In the mode, 3 numbers occurred repeatedly. Sum each of them up and divide by three.

Anonymous said...

If you count the alphabets in the three names Albert, Bernard, Cheryl you get 19, therefore the Answer is May 19.

Unknown said...

may 17 .... #key words. separately and respectively

Unknown said...

May 17...#Keywords. separately and respectively

Raphizzy said...

nawa o to dis kin essay

emmanuel said...

the answer is July 16th

Anonymous said...

May 19 nd August 17

Anonymous said...

Cheryls birthday is Bernard's birthday

Anonymous said...

july 16.....

Olaide Davies. said...

July 16

Amos Babafemi said...

The answer is July 16

Anonymous said...

Whaaaaat!! Won't even try to wrap my brain around this. Did you write PSLE when you were living in Singapore?

Alozie Paschal Okwara said...

Albert told mama ajobi that cheryl and bernard are near lagoon on the month of her birthday. So as Oba come dey with mama ajobi in spiritual, she tell am say bernard tell am the full birthday from no where. Meanwhile, me dey the next room with Oba daughter, come hear am. So finally, after much much, as I dey work the maths in Indonesia, I come get the answer. Its simple. July 16th. Na the same answer you get for your own maths?

Anonymous said...

Why?

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