It is currently Tue Jan 16, 2018 3:09 pm

 All times are UTC

 Page 1 of 2 [ 13 posts ] Go to page 1, 2  Next
 Print view Previous topic | Next topic
Author Message
 Post subject: Help, how do I explain this without algebraPosted: Mon Oct 05, 2015 7:09 pm

Joined: Thu Jan 09, 2014 7:29 pm
Posts: 66
Ben is 3 years older than his sister and a third of the age of his mother. His father is 4 years older than his mother and four times age of his sister. How old is Ben?

Top

 Post subject: Re: Help, how do I explain this without algebraPosted: Mon Oct 05, 2015 8:06 pm

Joined: Tue Apr 08, 2014 9:25 pm
Posts: 239
Why don't you want to use algebra?

Top

 Post subject: Re: Help, how do I explain this without algebraPosted: Mon Oct 05, 2015 8:11 pm

Joined: Thu Jan 09, 2014 7:29 pm
Posts: 66
mumsdarling2 wrote:
Why don't you want to use algebra?

I have solved the question by using algebra, but when I try to explain this to my 10 year old DS, he seems very confused. So I want to see if there is another way.

Top

 Post subject: Re: Help, how do I explain this without algebraPosted: Mon Oct 05, 2015 9:50 pm

Joined: Tue Jul 21, 2009 9:56 pm
Posts: 8538
I don't know.

Top

 Post subject: Re: Help, how do I explain this without algebraPosted: Mon Oct 05, 2015 11:10 pm

Joined: Wed Jan 18, 2012 11:41 am
Posts: 6839
Location: Essex
I drew a line with a mark a little bit in from the left labelled 'Sis'. Another mark a bit further over to the right labelled 'Ben'. At the right hand dot of the line, a mark labelled 'Dad' and little further to the left of 'Dad' a mark labelled 'Mum'.

As an aide memoire I put '?' under the section of line to the left of 'Sis', '3' between 'Sis' and 'Ben' and '4' between 'Mum' and 'Dad'. I then did 'hops' along the line to indicate that 'Ben' sits a third of the way from the left hand end to 'Mum' and 'Sis' a quarter of the way from that end to 'Dad'.

Having drawn the pretty picture to help visualise the problem, I just played around with ages for Ben, which when multiplied by 3 give an age for Mum four years less than the age for Dad (3 years less than Ben, ×4). It turns out that the siblings are just about the same ages as DD and DS2 and Mum and Dad are 8 and 5 years younger than myself and DH respectively

Possibly rather too long-winded for exam conditions, but it may help in transferring the solving of the problem to algebra, if that's what you want him to use.

_________________
Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read.Groucho Marx

Top

 Post subject: Re: Help, how do I explain this without algebraPosted: Tue Oct 06, 2015 5:53 am

Joined: Wed Sep 23, 2015 1:32 pm
Posts: 28
For these type of questions I had to teach algebra to my son. There are many questions you will come across which needs to be done by algebra to be time efficient. My son says that he encountered many questions in exam that needed algebra knowledge.
Basic algebra would be enough.

Top

 Post subject: Re: Help, how do I explain this without algebraPosted: Tue Oct 06, 2015 11:32 am

Joined: Tue Jul 21, 2009 9:56 pm
Posts: 8538
I drew a line with a mark a little bit in from the left labelled 'Sis'. Another mark a bit further over to the right labelled 'Ben'. At the right hand dot of the line, a mark labelled 'Dad' and little further to the left of 'Dad' a mark labelled 'Mum'.

As an aide memoire I put '?' under the section of line to the left of 'Sis', '3' between 'Sis' and 'Ben' and '4' between 'Mum' and 'Dad'. I then did 'hops' along the line to indicate that 'Ben' sits a third of the way from the left hand end to 'Mum' and 'Sis' a quarter of the way from that end to 'Dad'.

Having drawn the pretty picture to help visualise the problem, I just played around with ages for Ben, which when multiplied by 3 give an age for Mum four years less than the age for Dad (3 years less than Ben, ×4). It turns out that the siblings are just about the same ages as DD and DS2 and Mum and Dad are 8 and 5 years younger than myself and DH respectively

Possibly rather too long-winded for exam conditions, but it may help in transferring the solving of the problem to algebra, if that's what you want him to use.

Yes, I too was thinking of a trial and error method along those lines too. Worth being able to do things that way too - particularly the drawing to help visualise the problem - but, as you say, a bit of a mess in a timed test.

Equations with words rather than letters could do the job too - but really that's algebra too and just harder to write out.

Top

 Post subject: Re: Help, how do I explain this without algebraPosted: Tue Oct 06, 2015 12:21 pm

Joined: Wed Jan 18, 2012 11:41 am
Posts: 6839
Location: Essex
I also have the thought that this is a test of the candidate's ability to apply what they should have off pat by this age (3- and 4-times tables, albeit extending then beyond 12x) with an ability to apply logical thought to the problem. Is algebra in the KS2 curriculum (old or new)? The 'if 2 apples and 3 pears cost 98p and 5 kumquats and a raspberry cost 64p, then...' type question doesn't really count.

_________________
Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read.Groucho Marx

Top

 Post subject: Re: Help, how do I explain this without algebraPosted: Thu Jul 14, 2016 6:46 pm

Joined: Tue Feb 09, 2016 6:53 pm
Posts: 36
I have just come across this as well. Can someone please explain the algebra to me as we havent done that yet and could do with some help?

Thanks

Top

 Post subject: Re: Help, how do I explain this without algebraPosted: Thu Jul 14, 2016 8:05 pm

Joined: Wed Jan 18, 2012 11:41 am
Posts: 6839
Location: Essex
I have just come across this as well. Can someone please explain the algebra to me as we havent done that yet and could do with some help?

Thanks

This question has come up again in the last week or so. It's not really algebra.

http://www.elevenplusexams.co.uk/forum/11plus/viewtopic.php?f=15&t=47454&start=0

_________________
Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read.Groucho Marx

Top

 Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending
 Page 1 of 2 [ 13 posts ] Go to page 1, 2  Next

 All times are UTC

#### Who is online

Users browsing this forum: No registered users and 1 guest

 You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forumYou cannot post attachments in this forum

Search for:
 Jump to:  Select a forum ------------------ FORUM RULES    Forum Rules and FAQs 11 PLUS SUBJECTS    VERBAL REASONING    MATHS    ENGLISH    NON-VERBAL REASONING    CEM 11 Plus GENERAL    GENERAL 11 PLUS TOPICS    11 PLUS APPEALS    11 PLUS TUTORS    INDEPENDENT SCHOOLS    11 PLUS CDs/SOFTWARE    11 PLUS TIPS    PRIMARY    SEN and the 11 PLUS    EVERYTHING ELSE .... 11 PLUS REGIONS    Berkshire    Bexley and Bromley    Birmingham, Walsall, Wolverhampton and Wrekin    Buckinghamshire    Devon    Dorset    Essex    Essex - Redbridge    Gloucestershire    Hertfordshire (South West)    Hertfordshire (Other and North London)    Kent    Lancashire & Cumbria    Lincolnshire    Medway    Northern Ireland    Surrey (Sutton, Kingston and Wandsworth)    Trafford    Warwickshire    Wiltshire    Wirral    Yorkshire BEYOND 11 PLUS    Beyond 11 Plus - General    GCSEs    6th Form    University