2010
Wed
27
Oct

# GCE O Level Oct/Nov 2010 E-Maths 4016 Paper 2 Suggested Answers & Solutions

(41)
Posted at 11:24 pm

Meanwhile, at an underground bunker in a secret location

General Loi Mdm! We have incoming messages!

Read them to me, Sergeant Loi!

YES MDM!

Message #1: Complimentary spa session for all new treatment package sign-ups at ABC Beauty & Slimming Centre!

Message #2: Bring a friend and get a free 1 month gym membership at XYZ Fitness!

Message #3: FREE Yoga at …

*BIG WHACK ON THE HELMET POOOOOONG!!!*

Can you please skip all the spam and read only messages from the frontline for today’s O Level EMaths Paper 2????!!!!!!!

SORRY MDM! Here are the relevant messages!

2day’s paper so easy! haha. Can get A1

What we went through yesterday came out! I dunno can get A or B but I know I improved! Thx!

I found this paper very manageable too!

Nice I can do

Oh crap I lost 6 marks liao! Miss Loi: Aiyooh …

It appears our troops have fought well today, and our Enemy seems to be retreating. However, the papers seem too easy, and I now have to brace myself for the perennial “how many marks to get A1?” question.

Listen up Sergeant Loi! For those whose mathematical journey has ended, send them my ugly handwriting scribblings and ask them to check for mistakes!

MDM! YES MDM!

For our elite crack troops who still have to face two more days of Additional Mathematics Papers, send them this A-Maths Prayer so as to boost their morale!

MDM! YES MDM!

Hurry! Get the Apache helicopter to airdrop the leaflets now! And tell the pilot not to crash into the Woodlands field again!

MDM! YES MDM!
GANBATTE EVERYONE!

### Revision Exercise

To show that you have understood what Miss Loi just taught you, you must:

1. 2010
Oct
27
Wed
11:57pm

1

Oops! Before the lot of you start complaining, Miss Loi is amending the vertical m-axis of the graph in Q9 now - which should be 2 ≤ m ≤ 6 [Ok, amended]

2. mathslover says

2010
Oct
28
Thu
12:38am

2

oh no I made 2 mistakes

• 2010
Oct
28
Thu
2:00am

2.1

Oh no where? Where?

• mathslover replied to Miss Loi’s comment

2010
Oct
28
Thu
10:39am

@Miss Loi: vector, for some reason I got DB = (1 5) and I said DB perpendicular to DE since DB parallel to OE. The other 'fact' was |DB| and |DE| are the same cos both (1 5). Must've been blind.

Surface area. I got the slant height of the pyramid as sqrt (10^2 + 12^2). I did not recognise the 10 as the whole length, and what was needed was only half of it.

In fact the first attempt I got that funny area of triangle already, and forgot to multiply that by 4.

Sigh.

3. zette says

2010
Oct
28
Thu
2:23am

3

question 5 was tricky haha. a lot of people from my school thought angle CXD was the interior angle. i got tricked initially as well, but i'm glad i spotted the mistake.

• 2010
Oct
29
Fri
1:48am

3.1

@zette: Yes that sneaky little X really settled down nicely and camouflaged itself well on the main polygon didn't it?

It's like that polygon has got a parasite feeding on it or something

4. mathmathmath says

2010
Oct
28
Thu
9:30am

4

I made lots of careless mistakes. Yes and I got tricked by question 5 6marks gone...
I've checked the answers, I got around 85 for paper 2 and 70+ for paper... Can I still get my A1?

• 2010
Oct
30
Sat
9:09pm

4.1

Taking the worst case if you scored 70 for Paper 1, mathmathmath overall marks:

0.5 × (70/80 × 100%) + 0.5 × (85/100 × 100%) ≈ 86.3 (3 sig. fig.)

And according to The Seer this year

... estimating A1 to be 155/180, A2 to be 145/180, B3 to be 135/180 and B4 to be 125/180.

you've just made it! *throws confetti*

Note: The above is pure speculation and not to be taken seriously as the actual grade cut-offs, and furthermore Miss Loi has always advocated aiming for "85% for A-Maths and 90% for E-Maths to get an A1!", simply to buffer the possibility of unknown/hidden marks lost through backstabbing by the markers workings, significant figures etc.

5. Kelly says

2010
Oct
28
Thu
9:33am

5

The first fact for points DEB is that
1) Point E is the midpoint of D and B!
2) They all lie on the same line

• 2010
Oct
29
Fri
1:26am

5.1

@Kelly: Yuppy yuppy yup

Since
D, E and B are collinear (i.e. they all lie on a straight line)

and since
E is the mid-point of D and B

6. Lio says

2010
Oct
28
Thu
11:07am

6

Yo, what is the estimated bell curve for this paper...i have checked your solution..I got estimated 95% for paper 2 and 85% so is my probability of getting an a 2 high?
i hope can get an a 2 at least...a1 hmmm Doubth so...

7. cheryl says

2010
Oct
30
Sat
12:36am

7

Sorry i have to bother you with another question. For paper 2 the question on the tunnel that one. What will i get if my part a the answer oso wrong but if my method is correct for parts b and c.
And i heard from my friend who took last years o level that the mark to get an a1 was 80. Can this be true?

• 2010
Oct
30
Sat
7:43pm

7.1

@cheryl: Moved your P2 question to this Emaths P2 post.

The Q8 tunnel question requires the correct value of the reflex angle POQ obtained in (i) to sub into (1/2)ab sinC for the area of triangle in (ii), as well as the (1/2)r2θ for the area of the major segment in (iii).

And with just 2 marks on offer for each part, you're probably looking at ≤ 1 mark as M marks for each part provided you've written out your steps and formulae clearly.

8. 2010
Oct
30
Sat
12:30pm

8

Miss Loi has received a couple of emails from some who were caught out by the sneaky polygonic parasite X in Q5. One of which

Ive seen ur emaths paper 2 solutions however i do not agree to the answer for question 5 whole question because to my view.. 360 divide by number of sides 15 gives u the exterior angle but they are asking for the angle in the isosceles triangle so u have to get 180 minus away the ext angle to give u Interior angle 156 and den 180 minus int angle and divide by 2 for the 2 identical angle which will end up in 12 degrees thats my answer ,could u pls check the question again? Or did i mistaken the question.

Thank you

To illustrate further, what the above student (and most others who had been tricked by the nasty parasite X) had calculated is as follows:

However, as depicted in this earlier comment, Point X and the two lines CX and XD (the parts labeled in red below) are never part of the 15-sided polygon ABCDEF ... (notice the question didn't label the polygon ABCXDEF ..., and the absence of the equivalent signs || on CX and XD)

Hence ∠XCD is already an exterior angle of the polygon, and you can proceed to obtain ∠CXD via interior angles of isosceles triangle ΔXCD as shown below.

Sadly, the number of Q5 victims seems to have hit holocaustic proportions

9. liliting says

2010
Oct
30
Sat
3:59pm

9

?????????????? anyone hav an idea c6 is it = 50 mark/?

• 2010
Oct
31
Sun
12:53am

9.1

@liliting: Come ... come ... please cool down and let Miss Loi give you a big virtual hug.

While no one on this planet (apart from the faceless agents in the shady organization known as the SEAB) will know with 100% certainty the cut-off mark for each grade, it's time to do some selective reading and reproduce some quotes from that SGClub forum thread where you probably came from

Don't worry so much for moderation is more to help rather than drag students down. So long as u know u've done ur best, I figure that it is enough no matter the grades.

According to my teacher,

A1 and A2 gets moderated more.

B3 - F9 gets moderated too, but lesser.

IMO if you got 60+ you will never get C as every year moe gave large percentage of candidates get b3. C5-6 is generally given to punish those who didnt study and got 40-50 but give some face to you. My teacher said barely no one got D7 or E8/F9 unless you dont know any shit or just slept for the whole paper. So if your friend got C6 in actual fact they have failed the paper.

... focus on other subjects. the previous paper has ended. your fate is sealed the moment you finished your paper, collected back and send to Cambridge ... don't worry too much. if you know you have tried your best, done your best, then there is nothing to worry. why make yourself worry too much about such things when you can spend more time and brain power to concentrate on other subjects?

Now what you guys should do is:
1) Stay optimistic
2) Focus on other subjects

*squeeze squeeze liliting a little tighter*

Now can you please go and focus on your remaining papers and make sure you do well for them? GANBATTE!

10. Me says

2010
Oct
30
Sat
10:00pm

10

i got tricked by the polygon question!! so does that mean that i will get all wrong for that whole question?

11. Dean says

2010
Oct
31
Sun
12:49am

11

Does paper 1 weight higher than paper 2?

• cheryl replied to Dean’s comment

2010
Oct
31
Sun
1:00am

11.1

@Dean: No they have equal weightage.i
Ms loi: do you think this years bell curve will be lower than last year considering the tricky questions and the probability question in paper 1

12. Someone says

2010
Oct
31
Sun
11:49am

12

After checking the answers for paper 2....I think my A1 or A2 would be gone. I might get a B3....oh god. -.-"

13. 2010
Nov
1
Mon
12:09am

13

Just dug out another email from the pile ...

I refer to your solutions for paper 2 ,

6e) 42/11.4777

isn't it 4sig fig if use in working ?

like , 42/11.48

Cuz the last answer i got was 3 hours , 39 mins , 30s .
instead of yours : 3 hours , 39 mins , 33s

The instructions regarding degree of accuracy is a little brief on this year's question paper, but the following para remains on page 2 of SEAB's syllabus document:

Unless stated otherwise within a question, three-figure accuracy will be required for answers. This means that four-figure accuracy should be shown throughout the working, including cases where answers are used in subsequent parts of the question. Premature approximation will be penalised, where appropriate. Angles in degrees should be given to one decimal place.

In this case, Q6(d) specifically asked us to give the answer correct to three decimal places, which is 11.478 km/h.

While Miss Loi really, really doesn't enjoy interpreting the intention of such statements in a subject like Mathematics, using 11.48 in part (e) is akin to a premature approximation of 11.478 (even though it's 4 sig. fig.) when it's more accurate to use an accuracy of at least an order higher i.e. 11.4777 (4 d. p.) in this case.

As Miss Loi has said before, it's always dangerous to assume that a less accurate answer is a better answer, so always err on the side of more d.p./sig. fig. within your workings when in doubt.

Hope that Cambridge markers will be lenient on this though

14. dabulot says

2011
Jan
14
Fri
9:38pm

14

do u hav paper 1 ans?

• 2011
Jan
14
Fri
9:53pm
15. Kester Tay @PapaNigiri says

2012
Oct
24
Wed
7:40pm

15

Hi Ms Loi! The TYS answers says that Q10c (for the 2010 paper 2) is 7/295, but your (more trustworthy) answer says it's 7/590.

Can I confirm if it's an error with the TYS answer? Might have lost two marks in today's paper....BECAUSE I faithfully followed the TYS.

Irony much?

• 2012
Oct
25
Thu
8:52pm

15.1

That TYS of yours doesn't seem legit - see here.

16. caryn @carynsaw says

2012
Oct
26
Fri
3:50pm

16

maths is hard.......

### 6 Reactions

1. Miss Loi tweeted

2010
Oct
27
Wed
3:30pm

17

The 'O' Level 2010 EMaths Paper 2 solutions (as ordered by General Loi!): http://bit.ly/bN9UBE Please check for mistakes.

2. Low Qin Yuan tweeted

2010
Oct
27
Wed
3:54pm

18

RT @MissLoi: The 'O' Level 2010 EMaths Paper 2 solutions (as ordered by General Loi!): http://bit.ly/bN9UBE Please check for mistakes.

3. 2010
Oct
27
Wed
4:07pm

19

RT @MissLoi: The 'O' Level 2010 EMaths Paper 2 solutions (as ordered by General Loi!): http://bit.ly/bN9UBE Please check for mistakes.

4. Glendon Giam tweeted

2010
Oct
27
Wed
11:30pm

20

RT @MissLoi: The 'O' Level 2010 EMaths Paper 2 solutions (as ordered by General Loi!): http://bit.ly/bN9UBE Please check for mistakes.

5. Belle tweeted

2010
Oct
28
Thu
2:13am

21

@vinnigoh http://bit.ly/bN9UBE

6. 2011
Oct
28
Fri
2:12pm

22

RT @MissLoi: Retweet This Blog Post http://t.co/CfHxsieV

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