HABS maths exam 2009

11 Plus Maths – Preparation and Information

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greenvallley
Posts: 44
Joined: Sat May 02, 2009 7:14 am

HABS maths exam 2009

Post by greenvallley »

Can anybody help me out with question 30 of the above paper please?
It relates to the various combinations possible of 4 people seated around a table.
DS and I managed to work out the first part and got stuck on the 2nd part.
Any help gratefully received!
Thanks.
Minesatea
Posts: 1234
Joined: Sat Oct 31, 2009 12:08 am

Re: HABS maths exam 2009

Post by Minesatea »

Maths rusty but I think:


Part 2 - In part 1 there were four options, but Archibald only had one choice of seat. This time he has four choices therefore there are 4 x 4 = 16 possibilities.

Part 3 - First seat 4 possible occupants, second seat 3 , third seat 2, last seat only one

so 4 x 3 x 2 x 1 = 24
WP
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Joined: Thu Jan 03, 2008 9:26 am
Location: Watford, Herts

Re: HABS maths exam 2009

Post by WP »

We can simplify by seating in the order BCDA. B has 4 choices of seat. For each of these, C has 2 choices, and for each of those D has two choices, leaving only 1 seat for A. Therefore there are 4x2x2x1 = 16 possibilities.
Josa
Posts: 224
Joined: Mon Apr 28, 2008 10:57 am

Re: HABS maths exam 2009

Post by Josa »

It would have been great if Habs provided answers to their papers, will certainly make life easier for a maths novice like me :P
greenvallley
Posts: 44
Joined: Sat May 02, 2009 7:14 am

Re: HABS maths exam 2009

Post by greenvallley »

Thank you
How do I explain to DS why we need to multiply the possibilities?
I understand that in each place there will be different options but why do we need to multiply these?
This sort of question occurs in other papers also eg possible combinations from different coloured marbles
Does anybody have an easy way to explain to a 10 year old?
JaneEyre
Posts: 4843
Joined: Sun May 09, 2010 1:04 pm

Re: HABS maths exam 2009

Post by JaneEyre »

Sorry, I am really a novice in this 11+ preparation. I have never heard about these HABS maths papers and I had a quick look in the shop but I haven't been able to spot them. :x
What are they exactly? Are they harder than Bonds maths exams? Are they specifically used in some counties or can anybody preparing for 11+ in England benefit from using them? :?:
sherry_d
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Joined: Tue Sep 01, 2009 4:38 pm
Location: Maidstone

Re: HABS maths exam 2009

Post by sherry_d »

http://www.habsboys.org.uk/info/examina ... 11plus.php" onclick="window.open(this.href);return false; :wink:
Impossible is Nothing.
JaneEyre
Posts: 4843
Joined: Sun May 09, 2010 1:04 pm

Re: HABS maths exam 2009

Post by JaneEyre »

Oh I see!! Thanks, Sherry ! :D
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