Maths, Addmaths and Statistics: Post your doubts here!

[scouserlfc]

use an accurate vector diagram by drawing on a paper and i think the triangle forming is not a right angled triangle

 

[cristy!]

use an accurate vector diagram by drawing on a paper and i think the triangle forming is not a right angled triangle

actually we are not allowed to solve questions by accurate drawing!

 

[DANGERBP]

statistic guyz this question is killing me help !!!!
3. The time it takes girls aged 15 to complete an obstacle course is found to be normally
distributed with a mean of 21.5 minutes and a standard deviation of 2.2 minutes.
(a) Find the probability that a randomly chosen 15 year-old girl completes the course in less
than 25 minutes.
(3 marks)
A 13 year-old girl completes the course in exactly 19 minutes.
(b) What percentage of 15 year-old girls would she beat over the course? (3 marks)
Anyone completing the course in less than 20 minutes is presented with a certificate of
achievement. Three friends all complete the course one afternoon.
(c) What is the probability that exactly two of them get certificates?




plus he scewness of the data how can we know that ??

 

[beacon_of_light]

Hi could anyone plz solve june2010 Q10 p22 ... part b and c...also plz explain ...

http://www.xtremepapers.com/CIE/Cambridge O Levels/4024 - Mathematics/4024_s10_qp_22.pdf

thnx in advance

 

[CaptainDanger]

Hi could anyone plz solve june2010 Q10 p22 ... part b and c...also plz explain ...

http://www.xtremepapers.com/CIE/Cambridge O Levels/4024 - Mathematics/4024_s10_qp_22.pdf

thnx in advance

b) i)
There are different ways of doing this... You can use the formula if you wish...

a + (n-1)d
a is the first term...
d is difference...

So 10+(n-1)4
10+4n-4
6+4n

OR

find the difference between the values...

4 in this case...

Then write it as 4n+-(x) = 10

10 is the first value... S0 n =1

4(1)+-(x)=10

You have to find such x value which satisfies the equation... So it it is 4 in this case... Put it in the first equation and just take the left side of it... 4n+6

ii) The first difference is not the same for this part... The second difference is...

So its a quadratic sequence..

The formula for quadratic sequence is a+(n-1)d1+(1/2)(n-1)(n-2)d2
a is the first term of sequence
d1 1st difference
d2 2nd difference...

a is 2
d1 is 4
d2 is 2

2+(n-1)4+(1/2)(n-1)(n-2)2
Solve and you get n^2+n

c) Add the equations of b) i and b) ii

n^2+n +4n + 6
n^2+5n+6
n^2+2n+3n+6
n(n+2)+3(n+2)
(n+3)(n+2)
(n+2)(n+3)

 

[Steel Arm]

Plz can u tell me what are option codes?
I will be sitting for the end of year (Nov 2012) statistics o level
I know the syllabus code is 4040
But what about option code?

Please help me - have to fill in my form for exams...

 

[CaptainDanger]

Plz can u tell me what are option codes?
I will be sitting for the end of year (Nov 2012) statistics o level
I know the syllabus code is 4040
But what about option code?

Please help me - have to fill in my form for exams...

Choose 22 and 12...

 

[Steel Arm]

Choose 22 and 12...

No but is it not supposed to be a 1 letter or 2 letter code
Like AY for Add Maths....???

 

[CaptainDanger]

No but is it not supposed to be a 1 letter or 2 letter code
Like AY for Add Maths....???

Check that in the form you will be filling... Its Y...

 

[ROCK THE FIRST]

Q-8 (ii) -first find the y-coordinate of C using the equation you got in (i)
-then use vector method(vector matrices) to find CM(CM=OM-OC) and MD(MD=OD-OM) by supposing D(x,y)
-then use the equation 2CM=MD and find values of x and y.
Q-9 (ii)

Thanks

 

[scouserlfc]

actually we are not allowed to solve questions by accurate drawing!

U didnt get what i was saying i said make an accurate vector diagram and then use the trigonometry functions to get the answer by making an accurate diagram u will get to know whether the triangle forming is right angled or not and then u can solve,by making a diagram confusions are removed as it shows exactly whats going to happen and it barely takes two to 3 minutes !

 

[cristy!]

U didnt get what i was saying i said make an accurate vector diagram and then use the trigonometry functions to get the answer by making an accurate diagram u will get to know whether the triangle forming is right angled or not and then u can solve,by making a diagram confusions are removed as it shows exactly whats going to happen and it barely takes two to 3 minutes !

i m sorry for that n i do agree that drawing vector diagrams make it easy but the diagram it self is difficult to draw i mean if you give me the diagram i can find out the other stuff
could you like guide me in drawing the vector diagram for this?

 

[robinhoodmustafa]

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

Thank you!

Captain can You help me in a question .Will really appreciate
Q/Express 81 grams as a percentage of 3kg

 

[khizer shahab]

Captain can You help me in a question .Will really appreciate
Q/Express 81 grams as a percentage of 3kg

81 grams
3kg=3000 grams

this is unitary method

if 3000 g------------100%
then 81 g--------------- x
cross multiply and u would get ans=2.7%

 

[robinhoodmustafa]

ThankYou soo Much

81 grams
3kg=3000 grams

this is unitary method

if 3000 g------------100%
then 81 g--------------- x
cross multiply and u would get ans=2.7%

 

[snowbrood]

https://docs.google.com/viewer?url=...vels/4024%20-%20Mathematics/4024_s09_qp_1.pdf can anyone solve q15c??

 

[CaptainDanger]

https://docs.google.com/viewer?url=http://www.xtremepapers.com/CIE/Cambridge%20O%20Levels/4024%20-%20Mathematics/4024_s09_qp_1.pdf can anyone solve q15c??

Range is the difference between the smallest and largest value...

So subtract the smallest time from the largest one : 240-75= 165 seconds... 2 minutes 45 seconds...

 

[khizer shahab]

Q) A Farmer needs to fence off a region ABCDEF of his land as shown in figure. He uses a straight wall af,as one of the region.the remaining five sides AB,BC,CD and EF are made from wooden fencing,where AB=EF=X meters and BC=DE=5 meter. The sides AB and EF are right angles to the wall.the total lenght of wooden fencing is 80 meter
i) find CD in terms of x (3)
ii)show that y=292+68x-2x^2 (3)

 

[scouserlfc]

Q) A Farmer needs to fence off a region ABCDEF of his land as shown in figure. He uses a straight wall af,as one of the region.the remaining five sides AB,BC,CD and EF are made from wooden fencing,where AB=EF=X meters and BC=DE=5 meter. The sides AB and EF are right angles to the wall.the total lenght of wooden fencing is 80 meter
i) find CD in terms of x (3)
ii)show that y=292+68x-2x^2 (3)



View attachment 5784

first part :--
80=2x+10+CD
70-2x=CD

I can solve the first part with what u gave but what is y i think u missed something out here see again and then tell ill be waiting !

 

[khizer shahab]

first part :--
80=2x+10+CD
70-2x=CD

I can solve the first part with what u gave but what is y i think u missed something out here see again and then tell ill be waiting !

oh sorry i missed one line which is" the total area of the region ABCDEF is Y meter^2"

thnx for the 1st part!!