2012 GCE O Level Mathematics Paper 1 Suggested Solutions-第2页-O/A 水准-新加坡狮城论坛

冷风1985 LV8

发表于 23-10-2012 23:43:29 | 显示全部楼层

天使星发表于 23-10-2012 21:50
老师，如果 23(c) 47.9cm^2 对吗？

你好, 有精确值的,必须得保留全部数字.所以, 47.9 不可以.

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jsnleong LV4

发表于 24-10-2012 00:16:20 | 显示全部楼层

老师，

5a）if i did not reject a= -2 , i will not get the marks? I believe there is no half mark.. so its 0?

12a) so is it still correct to leave it as exact 161 1/3 ?

14) if part a) i did wrongly, then the entire qn (3m) will get 0? Or will they still give mark for (error carried forward) ?

How much do you think should get at least for p1 to secure a1? Thks!

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冷风1985

5a) -2 must be rejected. Otherwise, no marks. 12a) should't leave as 161 1/3. 14) errors will be carried forward for paper 1, which means you will not be given marks for the rest. 详情回复发表于 24-10-2012 10:06

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leochh LV2

发表于 24-10-2012 01:26:03 来自手机 | 显示全部楼层

hello, i think for q23, 47.9 is acceptable as the given area for the triangle is not exact either. is there any chance for me to get the mark if i have the working and 3sf indicated beside my answer? thx.

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冷风1985

You are completely correct. But we should take the given data as exact. (we can consider 21.3 cm^2 as exact value, but the length of the sides as estimated, right?) Your answer should be accepted. 详情回复发表于 24-10-2012 09:56

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JokingPanda LV1

发表于 24-10-2012 12:20:28 来自手机 | 显示全部楼层

老师
For qn 12a) 161 1/3 is already an estimate because you have to use the middle of the range of values they gave you which on its own is already an estimated value on itself. Eg: 140<x<150, there may be values like 143 or 148 but when u calculated the mean u have to use 145 which is estimating already.