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 Post subject: Question 36 Help
PostPosted: Tue May 05, 2015 4:46 am 
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Joined: Mon Dec 01, 2014 10:31 am
Posts: 17
Hi All,

Any help with question 36 would be much appreciated.

I think its 44cm (guess work) but just wanted to be sure.

http://www.nlcs.org.uk/userfiles/nlcs/p ... 202014.pdf

Thanks
Bill


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 Post subject: Re: Question 36 Help
PostPosted: Tue May 05, 2015 5:43 am 
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Joined: Sat Aug 10, 2013 11:46 am
Posts: 188
The answer is 48.

There is a way to do it using algebra, but for quickness in exams I often tell dd to put in numbers. So imagine the indent were 1cm, the total would be 28 for the horizontal lengths or if you put in 3, it would still be 28. The total vertical distance is 2*10.

Algebraically, calling the indent x.
Horizontal length of base = 10+4-x
Horizontal length of other 3 bits=10+x+4.
When you add these together the x cancels out giving 28.


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 Post subject: Re: Question 36 Help
PostPosted: Tue May 05, 2015 7:41 am 
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Joined: Mon Feb 12, 2007 1:21 pm
Posts: 11952
You do overcomplicate things russet!


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 Post subject: Re: Question 36 Help
PostPosted: Tue May 05, 2015 5:04 pm 
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Joined: Thu Jun 14, 2012 9:28 am
Posts: 121
I recall doing this question when dd was appearing for her 11+. The question always remained in my memory because it tested the mind. The first thing we did was to mark out all the known and unknown distances.

All vertical parts add up to 20cm. As far as the horizontal parts are concerned, there are some unknowns. The base line is more then 10cm. by, say "a"cm. The other unknown is the small bit above the 4cm. horizontal line. Let's call this "b". Thus, the equation for the perimeter will read :-

20 (verticals) + 10 + b + 4 + (10+a) = 44 + a + b.

Now look at the diagram again and see if you can find what "a+b" is.

I hope this helps.
Tagore


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 Post subject: Re: Question 36 Help
PostPosted: Wed May 06, 2015 9:36 am 
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Joined: Mon Dec 01, 2014 10:31 am
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Thanks.


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 Post subject: Re: Question 36 Help
PostPosted: Thu May 07, 2015 10:27 am 
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Joined: Sat Aug 10, 2013 11:46 am
Posts: 188
Guest 55. Which bit were you finding difficult to follow?


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 Post subject: Re: Question 36 Help
PostPosted: Thu May 07, 2015 6:35 pm 
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Joined: Mon Feb 12, 2007 1:21 pm
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Cheeky!

No need to use algebra ... the question is not designed for that.


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 Post subject: Re: Question 36 Help
PostPosted: Tue May 26, 2015 2:37 pm 
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Joined: Fri Jan 31, 2014 12:45 pm
Posts: 154
Did anyone confirm the answer to this? I got to 40 +(4-x) + (4-x), or 48 - 2x, but have no idea how to work out what x is...?


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