Estimating Imperial Conversions

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SunlampVexesEel
Posts: 1245
Joined: Fri Jul 06, 2007 9:31 pm

Estimating Imperial Conversions

Post by SunlampVexesEel »

From Bond "How to do 11+Maths"

A door is 5 feet 9 inches high. Which is closest to its height in metres? Circle the
correct answer.

1.5 m 1.6 m 1.7 m 1.8 m 1.9 m


We make it 1.8m; the book answer is 1.7m

(a) Are we right? (b) Is this a fair question?

Regards
SVE
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Guest55
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Joined: Mon Feb 12, 2007 2:21 pm

Post by Guest55 »

5ft 9inches is 69 inches

one inch is 2.5cm

69x2.5 = 172.5

so its 172.5cm which is nearer 1.7m

As a secondary maths teacher this seems hard ...
solimum
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Joined: Wed May 09, 2007 3:09 pm
Location: Solihull, West Midlands

conversion

Post by solimum »

However if you use the more accurate conversion rate

1 inch = 2.54 centimetres

then

69 inches is 1.7526 metres , which would (by convention) be rounded UP to 1.8m
Guest55
Posts: 16254
Joined: Mon Feb 12, 2007 2:21 pm

Post by Guest55 »

Usually children are taught to use 1inch = 2.5 cm as the conversion - as I said I think this is not really a 'good' question.
SunlampVexesEel
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Joined: Fri Jul 06, 2007 9:31 pm

Post by SunlampVexesEel »

Guest55 wrote:Usually children are taught to use 1inch = 2.5 cm as the conversion
I didn't know that. Is that the conversion factor built into these questions? i.e. a NFER convention?
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Mike
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Joined: Thu Jan 12, 2006 4:29 pm

Post by Mike »

Hi SLVE

If the question is a direct conversion question then you would need to use the most accurate approach.

If the question is an estimation then you need to use the easiest approach.

Regards

Mike
SunlampVexesEel
Posts: 1245
Joined: Fri Jul 06, 2007 9:31 pm

Post by SunlampVexesEel »

Mike wrote:Hi SLVE

If the question is a direct conversion question then you would need to use the most accurate approach.

If the question is an estimation then you need to use the easiest approach.

Regards

Mike
Mike,

In the question above... which approach would you recommend?
Animis opibusque parati
Mike
Posts: 625
Joined: Thu Jan 12, 2006 4:29 pm

Post by Mike »

Hi

Wouldn´t like to commit myself. This is a Bond question.

If it had been an NFER multiple-choice question it would almost certainly have been an estimate therefore I would use the easier method.

Regards

Mike
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