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2018 maths 11+ paper
Posted: Thu Oct 15, 2020 4:41 pm
by chelmsford dad
Can someone just clarify something for me on q14d
What is the percentage increase in the cost of buying dollars from June 23rd to June 26th?
June 23rd = $1.40
June 26th = $1.25
The answer is 12% which im assuming is 0.15/1.25
BUT i always thought % increase is difference/original amount
so i would have expected 0.15/1.40 or 10.7% ?
What am i doing wrong please ?
Re: 2018 maths 11+ paper
Posted: Thu Oct 15, 2020 10:25 pm
by Guest55
chelmsford dad wrote:Can someone just clarify something for me on q14d
What is the percentage increase in the cost of buying dollars from June 23rd to June 26th?
June 23rd = $1.40
June 26th = $1.25
The answer is 12% which im assuming is 0.15/1.25
BUT i always thought % increase is difference/original amount
so i would have expected 0.15/1.40 or 10.7% ?
What am i doing wrong please ?
Is that the whole question? You are correct in the way % increase/decrease is defined - however % increase and decrease is not taught at Primary so the question is not appropriate anyway.
Re: 2018 maths 11+ paper
Posted: Fri Oct 16, 2020 7:07 am
by ToadMum
I have a feeling that this is one of those where Guest55 may pop up to comment on its suitability as an 11+ question. Or at all...
Is that the whole question? Not the second part of one which e.g. asks how much it costs to buy a dollar on each of the dates, first?
Re: 2018 maths 11+ paper
Posted: Fri Oct 16, 2020 8:52 am
by Moderators
Please note (again) this section is for 11 plus maths not for the discussion of primary or NC maths.
Please stay on topic.
Moderators
Re: 2018 maths 11+ paper
Posted: Fri Oct 16, 2020 9:06 am
by ToadMum
Not wishing to be disrespectful, but one of the points that both G55 and I have made is surely a valid one, at least, that there appears to be part of the question missing?
Re: 2018 maths 11+ paper
Posted: Fri Oct 16, 2020 10:29 am
by mitasol
It is not disrespectful TM you have correctly identified the on topic point from the off topic point. We are always happy to give further guidance if required.
Re: 2018 maths 11+ paper
Posted: Tue Oct 27, 2020 10:37 am
by Pl1688
chelmsford dad wrote:
BUT i always thought % increase is difference/original amount
so i would have expected 0.15/1.40 or 10.7% ?
What am i doing wrong please ?
Imagine you wanted to buy $140. On the 23rd, you'd need 100 (probably pounds but could be any currency for purposes of this question). On the 26th, since $ has strengthened, you'd need 112 (140/1.25) which is your 12% increase (100 being your base/original amount). The question is asking for the % increase in cost of buying dollars, not the % change in the exchange rate.
Alternatively, you could ignore this and simply tell your DC that it's an inapppropriate question for 11+