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Edexcel AS Maths Paper 2- Stats and Mechanics *UNOFFICIAL MARK SCHEME *

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For question 7 the total time was 264 not 248

because (1/2x80x24)+(24xt)+(48x24x1/2)=4800

So 960+24t+576=4800

24t + 1536 = 4800

24t = 3264

t = 136s

Total time: 136+80+48=264s
Original post by ComicPizza
For question 7 the total time was 264 not 248

because (1/2x80x24)+(24xt)+(48x24x1/2)=4800

So 960+24t+576=4800

24t + 1536 = 4800

24t = 3264

t = 136s

Total time: 136+80+48=264s


Got that too
Original post by ComicPizza
For question 7 the total time was 264 not 248

because (1/2x80x24)+(24xt)+(48x24x1/2)=4800

So 960+24t+576=4800

24t + 1536 = 4800

24t = 3264

t = 136s

Total time: 136+80+48=264s


word to number the same **** as me XD
Original post by steveeem
but the velocity was never negative so how is the
displacement not the same as the distance?
genuinely confused


The displacement is never negative. If you plotted the graph of x against t, you'd see that the velocity is negative from t=1/2 to t=1, which means that at that point, the particle returns to its original position. So the distance travelled is 2 times the distance travelled from t=0 to t=1/2. The displacement from t=0 to t=1 is 0 but the distance is not that.
Does that help a bit?
did anyone else use completeing the square to prove the thing at the end?
Original post by nyxnko_
The displacement is never negative. If you plotted the graph of x against t, you'd see that the velocity is negative from t=1/2 to t=1, which means that at that point, the particle returns to its original position. So the distance travelled is 2 times the distance travelled from t=0 to t=1/2. The displacement from t=0 to t=1 is 0 but the distance is not that.
Does that help a bit?

Yeah thanks I realise where I screed up
out of 60? probs like 40 or 35. It's a new spec so we don't know.
how did people work out the mean
famm i think my way i did was wrongg :confused:
Original post by yixing
how did people work out the mean
famm i think my way i did was wrongg :confused:


is it not the sum of the frequency /n ?
People are asking if K was 1/3 or 3 and I got 2 :K:
Well at least I'm helping you all by pulling down the grade boundaries because I completely F***ed up on that paper
Hope everyone did great in the exam!

Propability question.

Part a) Simple tree diagram won't bother explaining.

Part b)

Working out:

(Given)
Propability of choosing a faulty item is 6%.

A: Chance of choosing is 10% and chance of being faulty is 9%.

B: Chance of choosing is 30% and chance of being faulty is 3%.

(working)
100% - (30%+10%) = 60% = chance of choosing C

10/100 x 9/100 = 9/1000 this is the propability of choosing A and it being faulty.

30/100 X 3/100 = 9/1000
This is the propability of choosing B and it being faulty.

9/1000 + 9/1000 = 9/500

9/500 + (60/100 x p) = 6/100

9/500 + 60p/100 = 6/100

9/5 + 60p = 6

60p = 4.2

p = 0.07 = 7%

Propability of part C being faulty is 7%.

Part c) forgot
I got 1/3 for k and was quite confident with my answer.
Original post by Jonathan9168
is it not the sum of the frequency /n ?


yeah man I'm sure i did that, but i just dont remember getting something like a 10.1/2 answer for it
have no idea :frown: yikes
Original post by Lemur14
2a I think was 6%?
I think 3 and 4 were the other way round? (not that it matters)
I wrote down that 3ai was 0.0599 and 3aii was 0.381 so that's probably your question 4.
5b I think was 0.005889898 so to 3sf that's 0.00589

I thought I got 264 for the distance in 7 but I might be misremembering.

Thanks for this!
Posted from TSR Mobile


Yep got 264 too
Original post by yixing
yeah man I'm sure i did that, but i just dont remember getting something like a 10.1/2 answer for it
have no idea :frown: yikes

I think it was 31 / 10 = 3.1
Then the deviation i used sqrt of Sum on f^2/n - (sum of f/n)^2
(edited 5 years ago)
Reply 55
i think you had to times the frequency by the interval, then divide by the total of the frequencies
Original post by Jonathan9168
I think it was 31 / 10 = 3.1
Then the deviation i used sqrt of Sum on f^2/n - (sum of f/n)^2

I've seen so many different answers for so many questions I'm not even sure anymore.
Hopefully whatever mean we got and using it to find the s.d would give some marks
It was only a 1 marker for the mean!! i think...
Low boundaries for the entire exam :tongue:
I got for question 3, the mean to be 5.something and the standard deviation to be 5.something aswell???
I said the N/A was equal to 0
(edited 5 years ago)
for question 5b I set up a binompdf X-B(60,0.15)
then I did

P(X>•30) = 1- P(X<•29) and got 0.00 lol. will I get any marks? How are ppl getting 0.0588???

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