Showing posts with label National Institute of Education. Show all posts
Showing posts with label National Institute of Education. Show all posts

Saturday, May 16, 2015

'Cheryl's birthday' poser is back with Part 2: Cheryl's age

Source Website: http://news.asiaone.com/news/singapore/cheryls-birthday-poser-back-part-2-cheryls-age
By Lee Min Kok, mklee@sph.com.sg, The Straits Times, Saturday, 16 May 2015

Solution: https://vulcanpost.com/242212/solution-cheryl-birthday-part-2/
By Jolene Hee, Vulcanpost.com on 15 May 2015


Part 2: What's Cheryl's age?
PHOTO: Part 2: What's Cheryl's age?
PS: Dr Yeo has clarified that the second line in the puzzle should read: “Cheryl: I have two younger brothers.”
Nanyang Technological University, Singapore with Un Cle Chai
By Lee Min Kok, mklee@sph.com.sg, The Straits Times, Saturday, 16 May 2015
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhc4GOE2B9egaOduI6twq7HLXRYk8b0TyLU6gnVeybMOcrnCOjLlHIezmSuOk0ep6PUqJFgFtiGNihFu9QSqbPduMLmCXOzhZqsNrbRT5YK3Wd_NQoi5_dViu6V7gK9f6vif1sN7k_QW-U/s1600/20150515_cheryls_age_ntufacebook.jpg
http://news.asiaone.com/sites/default/files/styles/full_left_image-630x411/public/original_images/May2015/20150515_cheryls_age_ntufacebook.jpg?itok=-_wqNbeu
http://news.asiaone.com/news/singapore/cheryls-birthday-poser-back-part-2-cheryls-age


SINGAPORE - First it was her birthday. This time, Cheryl's age is up in the air with a second part to the viral puzzle that made international headlines recently.

Nanyang Technological University (NTU) posted the question, which challenges people to work out Cheryl's age, on their Facebook page on Thursday night.

It also urged readers to grab a copy of its bi-monthly magazine, HEY!, to read more about Dr Joseph Yeo, the mathematics lecturer from the National Institute of Education who had set the now famous question as part of the Singapore and Asian Schools Math Olympiads (SASMO).

In an interview with The Straits Times last month, Dr Yeo shared that "Cheryl's birthday" was not a new logic problem and he had modified it by changing the names, date and context.

The question, which was leaked and made its way onto Facebook on April 12, generated a global buzz and was covered by media such as The New York Times, the BBC and the Guardian.

Question:
Albert and Bernard now want to know how old Cheryl is.

Cheryl: I have two younger brothers. The product of all our ages (i.e. my age and the ages of my two brothers) is 144, assuming that we use whole numbers for our ages. (Clue: 1)

Albert: We still don't know your age. What other hints can you give us?

Cheryl: The sum of all our ages is the bus number of this bus that we are on. (Clue: 2)

Bernard: Of course we know the bus number, but we still don't know your age. (Clue: 3)

Cheryl: Oh, I forgot to tell you that my brothers have the same age. (Clue: 4)

Albert and Bernard: Oh, now we know your age.

Solutions:
By Jolene Hee, Vulcanpost.com on 15 May 2015 and Bragadeesh

1) Cheryl: I have two younger brothers. The product of all our ages (i.e. my age and the ages of my two brothers) is 144, assuming that we use whole numbers for our ages. (Clue: 1)
(Clue: 1): Prime factorisation of 144 and list of possibilities
Prime factorisation of 144 and list of possibilities

Cheryl has two younger brothers and assuming order does not matter, there are lesser possibilities.
Cheryl has two younger brothers


2) Cheryl: The sum of all our ages is the bus number of this bus that we are on. (Clue: 2)
(Clue: 2): No use


3) Bernard: Of course we know the bus number, but we still don't know your age. (Clue: 3)
(Clue: 3): Sum of ages is not unique (i.e. it appear more than once). There left four possibilities.
3, 6, 8 and 4, 4, 9 add to 17
2, 8, 9 and 3, 4, 12 add to 19
Bernard: Of course we know the bus number, but we still don't know your age. (Clue: 3)


4) Cheryl: Oh, I forgot to tell you that my brothers have the same age. (Clue: 4)
(Clue: 4): 4, 4, 9
Cheryl: Oh, I forgot to tell you that my brothers have the same age. (Clue: 4)
So Cheryl is 9 years old
and her brothers 4 years old
The bus number is 17

By Lee Min Kok, mklee@sph.com.sg, The Straits Times, Saturday, 16 May 2015
This article was first published on May 15, 2015.
Get a copy of The Straits Times or go to straitstimes.com for more stories.



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Sunday, April 19, 2015

Meet the mathematics professor behind 'Cheryl's birthday' puzzle

By Chew Hui Min, chuimin@sph.com.sg, The Straits Times, Published on 18 April 2015 2:36 PM


Dr Joseph Yeo Boon Wooi, a mathematics professor at the National Institute of Education, is the man behind the viral math
PHOTO: Dr Joseph Yeo Boon Wooi, a mathematics professor at the National Institute of Education, is the man behind the viral math poser "Cheryl's birthday".
PHOTO: COURTESY OF DR JOSEPH YEO BOON WOOI
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDiefMkSGeY0nkePZj3lKAPZDg939bdQMtTlPwADGOPgWSH10MPQOSeUygn_cPp010PWGPYI6NR4wbW0vQAeq5t8fGr4i7qCNGmyLqTs33uDEdhFlDVPzNgLdd6lcd-0_CrDHfJ9-Qk2g/s1600/dryeo1e.jpg
http://www.straitstimes.com/sites/straitstimes.com/files/20150418/dryeo1e.jpg
http://www.straitstimes.com/news/singapore/more-singapore-stories/story/meet-the-mathematics-professor-behind-cheryls-birthday-p


SINGAPORE - The man behind the "Cheryl's birthday" viral poser is a mathematics professor from the National Institute of Education (NIE).

Dr Joseph Yeo Boon Wooi, who is in his 40s, is part of the panel for the Singapore and Asian Schools Math Olympiads (SASMO), the largest math competition here.

He helps set the questions each year for student "mathletes".

This year's competition took place on April 8. The puzzle in question was leaked, and subsequently posted on Facebook on April 11 by local TV presenter Kenneth Kong, who initially mistook it for a Primary 5 question.


Here’s a supposedly P5 logic question going viral on Facebook that will melt your brain
PHOTO: Here’s a supposedly P5 logic question going viral on Facebook that will melt your brain
Posted by Jonathan Lim on 12 April 2015
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqMVK7Bogj40Lw3NDaYhGdBWdrsr_-QSh4A4NO9tfABNUZUacSvFXcE9YcCxu1fBJjZdgm6JN2B-zTKHsXGrGIvFa4Q1m7w3LEKt1XasAPSsnlclEv-jlQQolpkd17kBeNJFlJ-N8_fm0/s1600/trick-question.jpg
http://cdn.mothership.sg/wp-content/uploads/2015/04/trick-question.jpg
http://mothership.sg/2015/04/heres-a-supposedly-p5-logic-question-going-viral-on-facebook-that-will-melt-your-brain/


Dr Yeo, a recipient of the prestigious Nanyang Excellence in Teaching Award in 2013 and first author of the New Syllabus Mathematics used in secondary schools, said he first chanced upon a Facebook post discussing the birthday logic problem on April 12.

But it did not ring a bell until he saw the photo of the question.

It has since been featured on international media such as The New York Times, The Guardian and the BBC, and was a top-trending story on US site Buzzfeed. On April 16, "Cheryl" even got her own cartoon on The New Yorker.

The Straits Times caught up with the media-shy math whiz and persuaded him to answer some questions about himself and how he came up with the viral hit that has confounded the world.

Dr Yeo's birthday, coincidentally (or not), falls on July 16 - the answer to the puzzle.

How did you come up with the question "Cheryl's birthday"?
I set the question based on guidelines given by SASMO.

This question, like all other questions we set, was vetted and approved by a panel of local and overseas experts from the SASMO Partners' League, which organises SASMO contests in their own countries.

"Cheryl's birthday" is not a new logic problem. There are various versions which others have modified. I am not aware of the original source. I modified it by changing the names, dates and context or storyline.

What do you think of the buzz it has generated?
I first saw someone on Facebook talking about the Cheryl's birthday logic problem on Sunday (April 12). It didn't ring a bell.

Then I saw a photo of the question. I was like, "Heh! This looks familiar!" I still cannot believe that the question has gone viral.

Which aspect of math do you specialise in?
I am a lecturer with the National Institute of Education. I specialise in training student teachers how to teach secondary school maths.

How did you develop your interest in maths?
It just comes naturally to me. I enjoy solving maths and logic problems.

By Chew Hui Min, chuimin@sph.com.sg, The Straits Times, Published on 18 April 2015 2:36 PM



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