Help needed with NFER 11C 47 & 11B 45

11 Plus Maths – Preparation and Information

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scooby1
Posts: 54
Joined: Thu Aug 13, 2009 12:49 am

Help needed with NFER 11C 47 & 11B 45

Post by scooby1 »

What is is quickest method to work out:

Q47 A map of Scotland is drawn to scale of 1:325,000.
how many CM on the map would show 65KM?

Q45 A map of Holland is drawn to a scale of 1:400,000.
What real distance is represented bt 1CM on the map?
beebee
Posts: 32
Joined: Fri Jul 24, 2009 2:10 pm

Re: Help needed with NFER 11C 47 & 11B 45

Post by beebee »

scooby1 wrote:What is is quickest method to work out:

Q47 A map of Scotland is drawn to scale of 1:325,000.
how many CM on the map would show 65KM?

Q45 A map of Holland is drawn to a scale of 1:400,000.
What real distance is represented bt 1CM on the map?
Q47

1:325,000 means 1 cm shows 325,000 cm,
converted to metres 1 cm shows 3250 metres
converted to km 1 cm shows 3.25 km

so to show 65 km
65/3.25 which gives 20 cm


Q45

using the same logic of converting to metres and then km
1cm represents 4km

That is how I would explain the problem to my children - I'm not sure they are quite up to this at the moment though.
yoyo123
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Joined: Mon Jun 18, 2007 3:32 pm
Location: East Kent

Post by yoyo123 »

we looked at a map book
(which conveniently had 1cm=25k 1:25000 scale ) on the front.

also those kitchen/bathroom planner grids you can get in B&Q with baths and units to scale. Once he had seen how it worked the calculations were easier.
scooby1
Posts: 54
Joined: Thu Aug 13, 2009 12:49 am

Post by scooby1 »

Thanks beebee, I understand them now.
scooby1
Posts: 54
Joined: Thu Aug 13, 2009 12:49 am

Post by scooby1 »

A great idea YOYO123 will pop into my local B&Q today.
scooby1
Posts: 54
Joined: Thu Aug 13, 2009 12:49 am

Post by scooby1 »

I thought I understood! However, I do not understand why you divide 65 by 3.25. Please explain. Thank you.
Ed's mum
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Joined: Mon Aug 13, 2007 11:47 am
Location: Warwickshire.

Post by Ed's mum »

Because every 1cm is 3.25km.

But you need to find out how many cms represent 65km (because that is the question)

Therefore you have to divide 65 by 3.25 to find out how many 3.25s go into 65km in order to find out the answer.

I hope that helps...
yoyo123
Posts: 8099
Joined: Mon Jun 18, 2007 3:32 pm
Location: East Kent

Post by yoyo123 »

IF 1 CM represents 3.25km

then 10cm represents 32.5km

32.5km is half of 65km

therefore 20 cm represent 65km
scooby1
Posts: 54
Joined: Thu Aug 13, 2009 12:49 am

Post by scooby1 »

I feel so silly now! :oops:
Twinkle
Posts: 580
Joined: Tue May 05, 2009 10:26 pm

Post by Twinkle »

My DS finds this type of questions very difficult. Can anyone point me to any sample questions /exercises on the internet? I have looked at Guest 55's useful maths websites and I have also googled but to no avail. Maybe I'm inserting the wrong terms in google /the websites????I have put in " maths scales" in. Anybody got any better ideas for a search term?

Thanks
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