Access it here if you’re having trouble accessing it on Facebook using your state-of-the-art smartphone 🙁

N.B. As usual, please, please leave a comment should you spot any mistake in the solution. As uttered by the High Priestess, she was still deep within a joss sticks session just an hour ago!

Next, she threw out another swarm of daggers …

Now for Paper 2: Here’s a list of possible topics that may appear for tomorrow’s Paper 2.

Algebra (changing the subject of a formula, simultaneous equations, completing the square)

Arithmetic (percentages, ratios, interest, money & hire purchase, speed etc. – may still appear even though P1 already contains some)

Problems involving quadratic equations

Trigonometry (three-dimensional problems, bearing, angles of elevation/depression etc.)

Probability

Statistics (cumulative frequency curve, box & whisker)

5) Will i still get the mark for value of a = 2 if i did not give two ans a=2 and a=-2 and then reject a=-2?

12a) Is it ok if i put 161 1/3 cm as an exact ans?

14) For entire bearing qn, if i got my point P wrong for first part, would they accept (error carried forward) for part b and c? And still award marks?

@Jason: Q5) Normally marks will be deducted for that (especially in school exams) but since this only carries 1 mark, the best you can hope for is this 1 mark to be fully allocated towards your correct answer of a=2 and nothing else (depending on the mark scheme).

Q12a) No problemo.

Q14) Unlikely, as the wrong position of P will affect the final answers of (b) and (c) which carries only 1 mark each.

Don't dwell on these and time to focus on your Paper 2 instead.

@Edison: This is something Miss Loi really doesn't like 😕

Apparently all Casio/Sharp calculators used in the exam halls showed 11.4378782 which appears to be exact (since not all digits are used).

On the other hand, a check with online calculators (like one or this one, as well as the ones residing in your Windows or Mac will yield something like 11.43787820165426 ...

As such, it's doubtful that Cambridge really intends it to be this way so Miss Loi believes some leeway will be given accordingly - especially if you've stated that clearly it's meant to be exact or approximated.

Hi Miss Loi!! For question 15, I forgot to write the properties such as the angle at centre = 2 angles at Oce, but since they are all only 1 mark questions, do I still get the mark?

@Despeate Math-er: Assuming you have the added security of your workings, it *shoooould* be fine in this particular case since the 1 mark involved would likely go towards the accuracy of your final answer, despite how yim chim your (well-meaning) school teacher used to mark your school exam paper.

Miss Loi though would still advocate students to always state the necessary properties in workings.

May I ask ,why is the question on radius of A which is 50% greater than radius of B is squared instead of being cubed when finding mass? And it is to find the ratio of these two unknowns 🙂

@Stacey: For Q24(b): Putting all ongoing discussions trying to dissect the areas, volumes, materials, "air space", blahblahblah of the cylinders aside, to state it simply, we've already established the formula for mass in part(a)(i) as follows:

M = 45r²

which means that the mass of each cylinder is directly proportional to the square of its radius i.e. M ∝ r² 😀

@Joel: The bearing in Q14(c) should not contain a decimal point in the first place since it's an exact measurement. Furthermore, this is consistent with the question's degree of accuracy since the given bearing (055°) contains no decimal place.

@asdfasf: Miss Loi has always forewarned students before an exam that "You run the risk of getting your ENTIRE vectors question marked ZERO if you don't do this! It has happened before in some unforgiving schools" (source).

After the exam, however, Miss Loi will tend to say that you may NOT even lose a mark for this (esp as this is O Level not school exam) depending on whether this is condoned by the mark scheme - likely it'll be accepted since there are no other variable a or b to confuse things in your working. 🙂

@rongrong: Whole numbers should be used whenever the final answer is exact, especially when the bearings given in the question usually do not contain any decimal place (i.e. you'd be 'artificially' adding a degree of accuracy if you leave your answer something like 090.0°)

However, non-exact answers in degrees should always be approximated to 1 decimal place. Remember also that your bearing should always contain 3 digits hor e.g. 090° 😉

* Please refer to the relevant Ten-Year Series for the questions of these suggested solutions.

About Miss Loi

Miss Loi is a full-time private tutor in Singapore specializing in O-Level Maths tuition. Her life’s calling is to eradicate the terrifying LMBFH Syndrome off the face of this planet. For over years she has been a savior to countless students … [read more]

Gratitudes

If not for you, I believe my math will still be a F9 grade. … [read more]

## 32 Comments

曜

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Hi Miss Loi !

5) Will i still get the mark for value of a = 2 if i did not give two ans a=2 and a=-2 and then reject a=-2?

12a) Is it ok if i put 161 1/3 cm as an exact ans?

14) For entire bearing qn, if i got my point P wrong for first part, would they accept (error carried forward) for part b and c? And still award marks?

Thanks for taking time to read!

曜

日

@Jason: Q5) Normally marks will be deducted for that (especially in school exams) but since this only carries 1 mark, the best you can hope for is this 1 mark to be fully allocated towards your correct answer of

a=2 and nothing else (depending on the mark scheme).Q12a) No problemo.

Q14) Unlikely, as the wrong position of

Pwill affect the final answers of (b) and (c) which carries only 1 mark each.Don't dwell on these and time to focus on your Paper 2 instead.

曜

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For Q22b) AB is an exact answer. Shouldnt the answer be AB = 11.4378782 ( 7 digits)?

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@Edison: This is something Miss Loi really doesn't like 😕

Apparently all Casio/Sharp calculators used in the exam halls showed 11.4378782 which appears to be exact (since not all digits are used).

On the other hand, a check with online calculators (like one or this one, as well as the ones residing in your Windows or Mac will yield something like 11.43787820165426 ...

As such, it's doubtful that Cambridge really intends it to be this way so Miss Loi believes some leeway will be given accordingly - especially if you've stated that clearly it's meant to be exact or approximated.

曜

日

Hi Miss Loi!! For question 15, I forgot to write the properties such as the angle at centre = 2 angles at Oce, but since they are all only 1 mark questions, do I still get the mark?

曜

日

@Despeate Math-er: Assuming you have the added security of your workings, it *shoooould* be fine in this particular case since the 1 mark involved would likely go towards the accuracy of your final answer, despite how

yim chimyour (well-meaning) school teacher used to mark your school exam paper.Miss Loi though would still advocate students to always state the necessary properties in workings.

曜

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Is ratio allow to have decimal?

曜

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@Tyler: Strictly speaking, ratios

cancontain decimals e.g. 1.5 : 1 but your final answer should be reduced to itssimplest formi.e. all integers.曜

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May I ask ,why is the question on radius of A which is 50% greater than radius of B is squared instead of being cubed when finding mass? And it is to find the ratio of these two unknowns 🙂

曜

日

@Stacey: For Q24(b): Putting all ongoing discussions trying to dissect the areas, volumes, materials, "air space",

blahblahblahof the cylinders aside, to state it simply, we've already established the formula for mass in part(a)(i) as follows:M= 45r²which means that the mass of each cylinder is directly proportional to the square of its radius i.e.

M∝r² 😀曜

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@Miss Loi: Okay 🙂 thank you! ^^

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Hi Ms Loi,

For paper 1, is it okay to leave decimal answers in 4 sig figure?

Thank you!

曜

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@Dudeism: Ummm ... your question is a little ambiguous as your decimal answer could be

These are stated in the instructions on the first page of your exam paper.

曜

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Hey Miss Loi,

For question 25(a), since they asked us to express 'as simply as possible', don't we have to extract out the common factors for the answers?

Or are both answers for 25(a)(i), (ii), (iii), accepted? I.e. extracted and not extracted.

Thank you!

Clarence 🙂

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@Clarence: Both should be fine IMHO 😀

曜

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For question 23 c, is it okay if I put 47.9 instead of the full thing?

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@Denton: Since it's exact, you shouldn't decrease its accuracy by rounding it from 47.925 to 47.9 *wags finger*

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For the bearing question in paper 1,if I did not put it in 1d.p. would we get penalised?

曜

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@Joel: The bearing in Q14(c) should not contain a decimal point in the first place since it's an exact measurement. Furthermore, this is consistent with the question's degree of accuracy since the given bearing (055°) contains no decimal place.

曜

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For 25a, i take out the common factor and put it as the answer

Will i get full marks?

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@---: No problemo!

曜

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Can the vectors be factorised?

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@winnie: No problemo! See comment before yours.

曜

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Hi...if i never put curly line under vector, is -1 for presentation only right? or -3? D:

曜

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@asdfasf: Miss Loi has always forewarned students

beforean exam that "You run the risk of getting your ENTIRE vectors question marked ZERO if you don't do this! It has happened before in some unforgiving schools" (source).Afterthe exam, however, Miss Loi will tend to say that you may NOT even lose a mark for this (esp as this is O Level not school exam) depending on whether this is condoned by the mark scheme - likely it'll be accepted since there are no other variableaorbto confuse things in your working. 🙂曜

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Hi! Can the statistic answer be 161(3sf)? cos I thought statistic answers should not leave in fraction? As in the case of the calculator too.

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@Raymond: For Q12(a), 163 (3sf) or 163⅓ is fine either way since it's after all a suitable estimate ^^

Which math guru told you that "statistic & calculator answers should not leave in fraction?"

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@Miss Loi: Oh haha because the calculator value is always in decimal if the stats function is used =p

曜

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Hi sorry but 1 more question from me. If my answer for qn 17c is male but I got 19.4% due to misunderstanding of the qn, will I get 1 or 0 mark?

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@Raymond: 1 mark

lorfor the males! ^^曜

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Hi! Do we leave bearing in whole number or it can contain decimal place?

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@rongrong: Whole numbers should be used whenever the final answer is

exact, especially when the bearings given in the question usually do not contain any decimal place (i.e. you'd be 'artificially' adding a degree of accuracy if you leave your answer something like 090.0°)However,

non-exactanswers in degrees should always beapproximatedto 1 decimal place. Remember also that your bearing should always contain 3 digitshore.g. 090° 😉All the best for your EMaths paper this Friday!