It is currently Fri Mar 22, 2019 4:12 am

 All times are UTC

 Page 1 of 1 [ 3 posts ]
 Print view Previous topic | Next topic
Author Message
 Post subject: Help with Maths Question- Divisibility relatedPosted: Fri Aug 10, 2018 6:32 pm

Joined: Mon Apr 11, 2016 6:45 am
Posts: 13
Can anyone help with the question please?

a) Take an even number. If you multiply it by 4, then you get the number P. If you half it then you get the number Q. P-Q is always a multiple of seven.
For example, if we choose 10, then P=40 and Q=5. 40-5=35, which is a multiple of seven. Explain why regardless of which even number you start with, you will always get a multiple of seven.

Many thanks

Top

 Post subject: Re: Help with Maths Question- Divisibility relatedPosted: Fri Aug 10, 2018 6:57 pm

Joined: Mon Feb 12, 2007 1:21 pm
Posts: 16126
Ahins wrote:
Take an even number. If you multiply it by 4, then you get the number P. If you half it then you get the number Q. P-Q is always a multiple of seven.
For example, if we choose 10, then P=40 and Q=5. 40-5=35, which is a multiple of seven. Explain why regardless of which even number you start with, you will always get a multiple of seven.

This is a totally inappropriate 11+ question: which school is this?

Take a general even number 2n

P = 4 x 2n = 8n
Q = 2n divided by 2 = n

P - Q = 8n - n = 7n hence always a multiple of 7.

Top

 Post subject: Re: Help with Maths Question- Divisibility relatedPosted: Fri Aug 10, 2018 10:16 pm

Joined: Mon Apr 11, 2016 6:45 am
Posts: 13
Thank you very much. Actually I do not think it is an 11+ question. I came across it from a few questions which I have collated over a period of time from different sources.Thanks for the quick response. Makes sense. Thanks so much.

Regards

Top

 Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending
 Page 1 of 1 [ 3 posts ]

 All times are UTC

#### Who is online

Users browsing this forum: No registered users and 2 guests

 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