Paper 42 (13th May) - Full Solutions

[notnek01]

sir in the speed question if we wrote.. 1743.8 will they minus a mark? and if we write 87.4?

You may lose a mark for 1743.8 (I would guess you won't) but you will definitely lose a mark for 87.4 because the question told you how to round.

 

[notnek01]

the paper was easy right? do u agree with me notneck?

No. It was one of the hardest IGCSE exams I've seen.

 

[sammer]

question 2)a)iii) is wrong its clockwise not anti-clockwise

 

[sammer]

q

24 hours have passed so here are full solutions to the 13th May IGCSE Maths Paper 42. These are my (IGCSE maths teacher) solutions and not the official solutions from CIE.

I’ll try to answer any questions regarding this paper but...

Since I don’t want to make any predictions that could be wrong, I will not answer any questions like, 'What will I need to get this grade?' or 'How hard/easy was the paper, what will the A boundary be?'.

I’ll only say that I thought it was a very hard paper, one of the hardest in recent years.

Here are the average total grade boundaries over the last 2 years:

A* : 174.7/200
A : 145.6/200
B : 114.8/200
C : 84.4/200

You can see my solutions to Paper 22 here.

question 2)a)iii) is wrong its clockwise not anti-clockwise, correct me if im wrong and i apologies in advance.

 

[Princess Raven]

THANK U! but still thank god for paper 2 because of that many can still get A* easily!

No. It was one of the hardest IGCSE exams I've seen.

 

[notnek01]

question 2)a)iii) is wrong its clockwise not anti-clockwise

You don't believe me so look here: http://en.wikipedia.org/wiki/Rotation_matrix under 'common rotations'.

 

[notnek01]

it really was not! i really wonder... why ppl thought it was difficult

Do you think all IGCSE exams are easy? Which paper 4 was harder than this?

I'm not saying that I found the exam hard, I'm saying that out of all the IGCSE exams I've seen, this is one of the hardest.

 

[notnek01]

ah yes if ur comparing it with other papers then yes it was!

So the only reason you thought it was easy is because you're very good at maths. Try to understand that most people in the world don't share your ability.

 

[notnek01]

notnek do u think a 199/200 would be a world ranking??

I have no idea.

 

[aaaamfa]

how many marks will i be loosing if i wrote 19 in the last answer

 

[vinod]

Sir how do we get the papers for other IGCSE subjects which are already been over?

 

[Shehab_]

At least 2 maybe 3.

2 out of 9 isn't there like Ecf for this type of questions
Isn't that a bit harsh?

 

[notnek01]

2 out of 9 isn't there like Ecf for this type of questions
Isn't that a bit harsh?

Maybe. I don't make the mark scheme.

 

[Sarah Jawrdawi]

I know you're not going to predict anything, but do you think there is any chance the curve for A* will be 165? Like any chance?

 

[notnek01]

I know you're not going to predict anything, but do you think there is any chance the curve for A* will be 165? Like any chance?

Yes, there's a chance.

 

[Sufiyancs]

Sir, no offense but ur last answer seems wrong because answer was something like 19.56
meaning completely 19 triangles can fit in.. that 0.56 is the space left after the last triangle
so
Pn-1 ==> 18
n= 19
i may be wrong

 

[notnek01]

Sir, no offense but ur last answer seems wrong because answer was something like 19.56
meaning completely 19 triangles can fit in.. that 0.56 is the space left after the last triangle
so
Pn-1 ==> 18
n= 19
i may be wrong

Look at P_1, P_2, P_3,... The bottom left corner of the triangle tells you the position of that triangle e.g. P_3 is the bottom left corner of the 3rd triangle.

So if the final triangle is the 19th then p_(n-1) = P_19.

 

[vinod]

sir ive written the SAS test for proving the triangles congruent!!!!!
Do u think ill lose any mark?

 

[Ozoman]

Sir, no offense but ur last answer seems wrong because answer was something like 19.56
meaning completely 19 triangles can fit in.. that 0.56 is the space left after the last triangle
so
Pn-1 ==> 18
n= 19
i may be wrong

You are counting them in a wrong way.
The first corner from the left of the triangle is the one that holds the triangle's number.
If you look at the 1st triangle you will see that it is numbered 1 on the left corner and it is P1.
Therefore P19 would also be numbered on the left corner not the right one.
We know that the left corner is n-1.
We know that the last triangle is numbered 19.
n-1=19
n=20

 

[Ratatat]

Sir, no offense but ur last answer seems wrong because answer was something like 19.56
meaning completely 19 triangles can fit in.. that 0.56 is the space left after the last triangle
so
Pn-1 ==> 18
n= 19
i may be wrong

n = 20 is correct.

If you look, the triangle number is shown by the P value on the left of a triangle, so Pn-1 = the number of triangles = 19, so n= 20
(if that makes sense)