Maths, Addmaths and Statistics: Post your doubts here!

[OakMoon!]

Re: O'level Maths, Addmaths and Statistics help available he

Yes, these lectures are absolutely magnificent. Eventhough, they are not a help for me but this was one chapter that constantly bugged me in my final year of O-levels. Thankfully, it didn't come in my final exam in June 2010. I wish I could have gotten these notes last year, it would have saved alot of my time.

 

[rafae]

Re: O'level Maths, Addmaths and Statistics help available he

Can someone help me out on this:

16 Dai played three games of cricket.
His mean score was 9 runs.
His median score was 8 runs.
His highest score was 7 runs more than his lowest score.
(a) Find the number of runs he scored in each of the three games.



(b) Dai batted in a fourth game.
The mean of his four scores was 11 runs.
Find the number of runs that Dai scored in the fourth game.




And secondly Q22 of this : http://www.xtremepapers.me/CIE/Cambridg ... _qp_11.pdf

 

[abcde]

Re: O'level Maths, Addmaths and Statistics help available he

Can someone help me out on this:

16 Dai played three games of cricket.
His mean score was 9 runs.
His median score was 8 runs.
His highest score was 7 runs more than his lowest score.
(a) Find the number of runs he scored in each of the three games.
(b) Dai batted in a fourth game.
The mean of his four scores was 11 runs.
Find the number of runs that Dai scored in the fourth game.

(a) Total number of runs in all 3 games = mean score x no. of games
= 9 x 3
= 27
Let his lowest score be x.
=> highest score = x + 7
=> middle score = 8 (the median tells you that).
=> x + 8 + (x + 7) = 27
=> 2x + 15 = 27
=> x = (27 - 15)/2 = 12/2 = 6.
So Dai's scores are 6, 8 and 13, respectively.

(b) Score in fourth game = total score in all four games - score in first 3 games
= (11 x 4) - (9 x 3)
= 44 - 27
= 17.

 

[rafae]

Re: O'level Maths, Addmaths and Statistics help available he

Can someone help me out on this:

16 Dai played three games of cricket.
His mean score was 9 runs.
His median score was 8 runs.
His highest score was 7 runs more than his lowest score.
(a) Find the number of runs he scored in each of the three games.
(b) Dai batted in a fourth game.
The mean of his four scores was 11 runs.
Find the number of runs that Dai scored in the fourth game.

(a) Total number of runs in all 3 games = mean score x no. of games
= 9 x 3
= 27
Let his lowest score be x.
=> highest score = x + 7
=> middle score = 8 (the median tells you that).
=> x + 8 + (x + 7) = 27
=> 2x + 15 = 27
=> x = (27 - 15)/2 = 12/2 = 6.
So Dai's scores are 6, 8 and 13, respectively.

(b) Score in fourth game = total score in all four games - score in first 3 games
= (11 x 4) - (9 x 3)
= 44 - 27
= 17.

Thank you so much!

 

[abcde]

Re: O'level Maths, Addmaths and Statistics help available he

You're most welcome!

 

[olevels]

Re: O'level Maths, Addmaths and Statistics help available he

Can anyone provide notes for Transformation (maths) ? :Bravo:

 

[abcde]

Re: O'level Maths, Addmaths and Statistics help available he

I could find this for you: http://www.astarmathsandphysics.com/gcs ... ments.html

 

[abcde]

Re: O'level Maths, Addmaths and Statistics help available he

And this booklet covers all notes comprehensively:

 

[mrgreedywolf]

Re: O'level Maths, Addmaths and Statistics help available he

Asalam-o-Alikum to all.

Ok need help on the following questions,

link to qp paper http://www.xtremepapers.me/CIE/Cambridg ... _qp_12.pdf
link ms http://www.xtremepapers.me/CIE/Cambridg ... _ms_12.pdf


ok the questions are

q 24 last part, how do we get it ?

q25 last part

Thanks in advance. :good:

 

[xhizors]

Re: O'level Maths, Addmaths and Statistics help available he

hey abcdes y u have add x to 7 plz give me explanation in Q16 above
quote"=> highest score = x + 7"

 

[abcde]

Re: O'level Maths, Addmaths and Statistics help available he

hey abcdes y u have add x to 7 plz give me explanation in Q16 above
quote"=> highest score = x + 7"

The question states that his highest score was 7 runs more than his lowest score. I took the lowest score as x. So highest score = (x + 7).
P.S. I urge you to use correct user names! Here,its 'abcde', not 'abcdes'. Thank you.

 

[xhizors]

Re: O'level Maths, Addmaths and Statistics help available he

thanks,, hmm sry

 

[Dissent]

Re: O'level Maths, Addmaths and Statistics help available he

Would appreciate some help figuring out the question below:

 

[OakMoon!]

Re: O'level Maths, Addmaths and Statistics help available he

Asalam-o-Alikum to all.
Ok need help on the following questions,
link to qp paper http://www.xtremepapers.me/CIE/Cambridg ... _qp_12.pdf
link ms http://www.xtremepapers.me/CIE/Cambridg ... _ms_12.pdf

ok the questions are
q 24 last part, how do we get it ?
q25 last part

Thanks in advance. :good:

For the first question you have to realize that DA='q'AE. Where q is a real number, since the three points are collinear.
DA=3p+q/3 and AE=P+kq
You make take the ration of DA:AE. 3(p+q/3)=q(p+kq). The base vectors have to be the same so p+q/3=p+kq and then you state that k=1/3 as the coefficients on both the sides have to be same.

For the second question, first of all ind the deceleration of the journey after 60s. Acceleration from t=0 to t=20=u/20.
Deceleration after 60s is half of the acceleration so, (u/20)/2=u/40.
Now find the time to decelerate to the speed, u/4. Apply the acceleration formula: -u/40=[(u/4)-u]/x
You find x to be 30s. This is the time of deceleration, add 30 to the time for the previous journey i.e.t= 30+60=90

 

[OakMoon!]

Re: O'level Maths, Addmaths and Statistics help available he

Would appreciate some help figuring out the question below:

LOL! Is this from the June 2010 exam? This was my only mistake in both the papers when I gave it back in last June. Sad memories.

To make 2^3*3*7 a square number you have to multiply it by 3, 7 and 2 so that it becomes (2²*3*7)² which is a square number. So n=2*3*7=42.

The first non integer n would have been; 3*7/2 that I wrote.

 

[abcde]

Re: O'level Maths, Addmaths and Statistics help available he

Would appreciate some help figuring out the question below:

In order for 168 n to be a square number, each of its prime factors must have an even power.
168 = 2^3 x 3 x 7
You can make 168 a square number by multiplying it by 2 x 3 x 7 as 168 would then become 2^4 x 3^2 x 7^2.
=> n = 2x 3 x 7 = 42.
Sorry, Hamid, I didn't know you were replying when I started out!

 

[OakMoon!]

Re: O'level Maths, Addmaths and Statistics help available he

@abcde: For it to be a square number the factors should have an even power and not only a minimum power of 2.

 

[abcde]

Re: O'level Maths, Addmaths and Statistics help available he

Agreed. Thank you!

 

[mrgreedywolf]

Re: O'level Maths, Addmaths and Statistics help available he

For the first question you have to realize that DA='q'AE. Where q is a real number, since the three points are collinear.
DA=3p+q/3 and AE=P+kq
You make take the ration of DA:AE. 3(p+q/3)=q(p+kq). The base vectors have to be the same so p+q/3=p+kq and then you state that k=1/3 as the coefficients on both the sides have to be same.

How did you assume DA= 3p + q/3 ? where as DA=3p+q,
I couldnt understand how you made this ratio 3(p+q/3)=q(p+kq) and deduced it to p+q/3=p+kq ?

 

[abcde]

Re: O'level Maths, Addmaths and Statistics help available he

Hey, maybe this could help you mrgreedywolf:
You know that DA = 3p + q and AE = p + kq.
Since D, A and E are collinear, DA is parallel to AE. So their vectors must have a constant ratio. Compare the coefficients of p in DA and AE. They have the ratio 3 : 1. So the coefficients of q must also have that same ratio.
=> 3/1 = 1/k
=> k = 1/3.
Clear?