*Loud droning noise overhead*

A very big package just got air-dropped from Jφss Sticks Airways Flight JS296!

Click the button and grab it here!

Latest version:

- 1.3: added “marks” to the answer for interquartile range in Q23(a) for completeness’ sake.
- 1.2: added brackets to answers of Q15(b) to make all terms ‘inclusive’ to the radian unit.
- 1.1: reflect changes in Q22(b)

As usual, please leave a comment should you spot any mistake in the solution – Miss Loi was still teaching at The Temple until an hour and a half ago!

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

- Changing the subject of a formula
- Quadratic equations (word problem)
- Simple algebraic fractions & equations
- Number patterns
- Inequalities

Application of mathematics in practical situations

- Profit & Loss
- Compound interest & simple interest
- Money exchange
- Hire purchase

- TOA CAH SOH
- Sine/Cosine Rule
- Area of triangle
- Bearings
- Angles of elevation/depression
- Shortest distance

- Mensuration
- Angle properties of polygons + finding number of sides of polygons
- Vectors
- Probability tree diagram
- Possibility diagram

- Graph sketching on graph paper

One down, one or three (depending on whether you take AMaths) more maths papers to go!

**ALL THE BEST & GANBATTE!**

## 28 Comments

曜

日

I would like to ask if 2 s.f. or 3 s.f is suitable for question 22bi and 22bii

曜

日

@Han LowJumper Zhong Liang: Hah! It should be 2 sig. fig. for Q22(b)(i) & (ii) since

When quantities are multiplied or divided, the number of significant figures (i.e. the

reasonablelevel of accuracy) in the answer is equal to the number of significant figures in the quantity with the smallest number of significant figures.Miss Loi has amended the answers to Q22(b) and uploaded version 1.1 of the solution to reflect this (with an added note at the relevant spot).

Thanks for pointing this out!

曜

日

Hello ms loi.

For qn 22bii, isit a must to leave in standard form? The question didnt state.

曜

日

@Maisie: While Miss Loi thinks it's fine not to leave it in standard form (the question didn't ask for it as you said), your final answer should be in 2 sig. fig. i.e. 22 000 000 to achieve a "sensible degree of accuracy" (yeah I know this is mentioned in part (b)(i) but the principle still holds), since like in (b)(i), the accuracy of your answer is still limited by the 2 sig. fig. of your 6.1 × 10

^{7}.曜

日

Miss loi, for question 12(b) , I didn't see the volume should be change to it's original form, which is 14.5. But I did change the 43 to 43.49 and I got 2.9 which is the wrong answer. Will I get 1 mark for it?

曜

日

@Hi....: Q12 reminds Miss Loi of the

lower/upper boundsquestions of old.The mass of the glass block,

m, could be anywhere between 42.5 ≤m< 43.5. Note the < sign for 43.5 as technically the upper bound can never be reached since we have to round up again to 44 when we're at 43.5.So strictly speaking, largest possible mass is 43.499999999 .... which Miss Loi wrote as 43.49 (with a dot over the 9) to indicate the recurring decimals.

Not sure if the mark scheme is going to be particular about this though ...

曜

日

@Miss Loi: Oh okay. Thanks.

曜

日

For qn 5, the answer should be an expression right?

曜

日

@Discuss: ??? The question did ask to "find an expression in terms of

xandy..."Perhaps you're asking if "litres" should be included?

In this case, many TYS solutions for very similar "find an expression in terms of ..." word problems include the unit as

part of the algebraic expression- so Miss Loi tends to include them just to be safe.But then again, there are also some that don't include them so Miss Loi feels this isn't critical unless we're specifically told to do so in the question (which we weren't in this case).

Would welcome feedback from anyone who has received a clear directive from your school/cher/Maths HOD Overlord on this 😛

曜

日

Question 12b, if you times 3.00 by 15 again, it wouldn't be possible anymore. Some people answered with 2.99 instead. So, which one issit?

曜

日

@Kekeke: See below.

曜

日

FR QN 8A, CAN OR NOT IF I WRITE 8C/D ?

曜

日

@JACK: The answer is d/(8c), and you asked if you can write (8c)/d. You say

leh???曜

日

for Qsn 22b, they won't accept 3 sig fig at all? how many marks will i lose for not putting in 3 sf?

曜

日

@abhishek: See below 🙂

曜

日

hi, for q12b, why is the answer 3.00 and not 2.99 since 3.00x14.5=43.5 which would not result in 43g?

曜

日

@Peace: and why would the sensible accuracy refer to 2sf and not 3sf as stated in the instructions?

曜

日

@Peace: As for why it's 2sf and not 3sf for Q22(b), please see above 🙂

曜

日

@Peace: Miss Loi thinks we'd all agree that the '

exact' greatest possible mass of 1 cubic cm of glass is 2.99999999999999999 ... g.But we have to leave this final answer in 3 sig. fig. (as per the instructions), thus we round it to 3.00.

However by doing this there is already a

loss of accuracyin this value of 3.00.So if you work backwards by multiplying this already "inaccurate" 3.00 by 14.5 will yield a value of 43.5 whose accuracy has been affected by the earlier rounding of 2.999 ... to 3.00. In this case this "43.5" is actually

round upof something like 43.499999 ...This is why it has always been stated in our syllabus document that

“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.”... which essentially means final answers should not be used directly to compute something else - something which Miss Loi has discussed blogged about before.

曜

日

Hi miss loi,

I've a few question to ask you:

1)Can predict the score needed for maths paper to get A1 and A2.

2)Would i get my marks if i did not label the bisector

3)Can i leave 2a part (II) as 22344322 instead of

Thanks!

曜

日

Hi miss loi. Can I leave my answer in standard form, 1.34 x 10^2, for question 22(a)?

曜

日

For qn 18ai,ii and iii, what if i put my answer just as 9, -2 and 1/4 respectively?

曜

日

@Hisham: Noooo your 7s have gone missing! You're supposed to "express your answer as a power of 7"!

曜

日

Hello! If i did not put the units for the questions on angles (158-x), will i be penalize?

And the interquartile range should there be "marks"?

>Darn! I got the "P" wrong. DX

曜

日

@Hi: In school exams, absence of essential units (like the ° sign in this case) will cost you marks (often half a mark) but as always in one-mark questions - it'll depend on how strict Cambridge's gonna be on this :\

For the interquartile range in Q23, it's arguable if the word "marks" is considered an "essential" unit but seeing it being a 2-mark question and that most textbook answers include it, Miss Loi has included it as well in v1.3 for completeness' sake.

曜

日

Hi Miss Loi, I calculated my total marks for p1 and p2 and i got over 60 but less than 65, you think that will be a B4 or B3?

曜

日

Hi, question 24 c) dat speed time graph , can i link the 3 line together? and should i label the bisector ? 18aii) can i put as 1/7^2 ? And u think that 80 marks can get A?

曜

日

pls reply pls , or else i gonna haf a moody holiday lol