This discussion is now closed.

Check out other Related discussions

Mega A Level Maths Thread MK II

What puzzles me is why does the answer of the book for the first part include various arrangements of the same sequence and we take into account the fact that the same sequence could be arranged in different ways in the second part?

I don't quite understand what you're asking :s-smilie:

For the first part, it just asks for the total number of 8 sequences chosen from 52 cards - you could have PPPPPPPPP or PPPPEEEE or OOPEOPEO, etc.

For the second part, we only consider the sequences which have 3P, 3O, 2E. Try to imagine having said deck of cards in your disposal and choosing the cards that would yield the required sequence. Ok, so now we want to consider the suquence of 3P, 3O and 2E. Start off with the most basic one - choosing 3Ps sequentially then 3O sequentially then 2O sequentially. You have 12 Ps, and you want to choose 1 P to start off with. How many ways can you do this? It's simply 12C1. Then you replace the card you took and want another P. The number of ways you can do this is 12C1. And again to get the 3rd P, 12C1 - so the number of ways you can choose 3P is 12C1 x 12C1 x 12C1 = 12^3. You rinse and repeat for the Os and Es to get 12^3 x 20^3 x 20^2. Now, this is only the number of ways you can choose to get the specific sequence PPPOOOEE. Another valid sequence is PPEEOOOP for example. Rather than just listing all these out, the number of ways you can arrange these is 8!. But order is important here - go back to sequentially choosing the cards from the deck to construct the sequence. You could choose 1P (12C1) but then choose another P from the one you had previously chosen (if that makes sense :s-smilie:

), which the 8! takes into account. So this could yield another sequence of say PPPOOOEE - but this is the exact same sequence as we first constructed. As order does matter, we divide by 3! x 3! x 2! as there are 3P, 3O, 2E - hope that helped

Reply 121

Bixel

5

Original post by DJMayes

Your first point is correct. However,

F= \mu R

does not necessarily imply that the object is in motion - it could be in limiting equilibrium.

Ah brilliant, thankyou DJ!
My mechanics teacher was not fantastic this year, they missed out a lot of these little bits!

Reply 122

Bixel

5

Original post by L'Evil Fish

Yeah

there are more... But didn't want to list everyone :lol:

Who's ready for their C1/M1 tomorrow? :smile:

C1/M1 one after another is going to fry my brain!

Reply 123

Ateo

9

Original post by Felix Felicis

...

I understood your solution. Perhaps I should be more clear about what I was saying. For the first part, you could have PPPPPPPE and PPPPPPEP as the exact same sequence just in a different arrangement. The 52^8 includes repeated arrangements.

Reply 124

L'Evil Fish

OP

18

Original post by Boy_wonder_95

Ahh this takes me back, no better way to start Maths A Level than with C1 and M1 :')

Original post by Bixel

C1/M1 one after another is going to fry my brain!

Don't let it fry! Is C1 first?

Reply 125

Felix Felicis

13

Original post by Ateo

I understood your solution. Perhaps I should be more clear about what I was saying. For the first part, you could have PPPPPPPE and PPPPPPEP as the exact same sequence just in a different arrangement. The 52^8 includes repeated arrangements.

The first part asks for all the different arrangements, hence order doesn't matter.

Reply 126

username937760

16

Original post by Boy_wonder_95

Ahh this takes me back, no better way to start Maths A Level than with C1 and M1 :')

If you'll excuse my French, why the flying flamingo are you getting nostalgic about the fact you're now in the summer of AS and reminiscing about the good old days? You're making me feel old as an A2 student... :lol:

Reply 127

Ateo

9

Original post by Felix Felicis

The first part asks for all the different arrangements, hence order doesn't matter.

The second part then asks how many of those sequences (all their arrangements) will satisfy the given condition, and in this part, we ignore the various arrangements and divide as you have shown. I just feel that the question could be a bit clearer.

Reply 128

Bixel

5

Original post by L'Evil Fish

Don't let it fry! Is C1 first?

Yeah, C1 first!

Reply 129

Moon1ight

15

Done 7 c1 papers twice - that's 14 papers I've done for C1 - should I feel prepared and confident ?

Posted from TSR Mobile

Reply 130

blueberryyums

I am doing M1 CIE tomorrow and I have another paper. Are 10 past year papers enough to get me ready or an A for M1? The paper is out of 50 and on average, I lose 5 marks or spend a lot of time thinking on certain questions. (An A varies for 37 - 44 out of 50) I was wondering if I should stop with the papers and review the ones I have done because they all seem fairly similar..?

I've also got another paper tomorrow, Economics MCQ (CIE, so edexcel students, do not panic :smile:

), and I wanted to do some more of that maybe at 6 or 7pm.

What do you think?.. I don't want to decide because I might be biased and choose the subject I prefer more and abandon the other.

Reply 131

upthegunners

10

http://www.thestudentroom.co.uk/showthread.php?t=2348838

anyone? :colondollar:

Reply 132

Bixel

5

Original post by upthegunners

http://www.thestudentroom.co.uk/showthread.php?t=2348838

anyone? :colondollar:

As far as I know, you get marks for the answer and the workings, so just to be safe make sure you do your working out to the full. Not sure how you'd do a whole Maths AS paper in your head anyway!

Reply 133

joostan

13

Original post by krishkmistry

Done 7 c1 papers twice - that's 14 papers I've done for C1 - should I feel prepared and confident ?

Posted from TSR Mobile

Probably

Reply 134

username937760

16

Original post by blueberryyums

I am doing M1 CIE tomorrow and I have another paper. Are 10 past year papers enough to get me ready or an A for M1? The paper is out of 50 and on average, I lose 5 marks or spend a lot of time thinking on certain questions. (An A varies for 37 - 44 out of 50) I was wondering if I should stop with the papers and review the ones I have done because they all seem fairly similar..?

I've also got another paper tomorrow, Economics MCQ (CIE, so edexcel students, do not panic :smile:

), and I wanted to do some more of that maybe at 6 or 7pm.

What do you think?.. I don't want to decide because I might be biased and choose the subject I prefer more and abandon the other.

0 past papers are enough to get some people an A. 50 past papers are not enough to secure others an A. The question is not whether you have done enough past papers, it's now comfortable you feel with regards to M1 tomorrow. If you do not feel comfortable, then do some more. If you do, your time would be better spent revising Economics if you're less comfortable with that.

Reply 135

MathsNerd1

17

My lord this thread is on fire today! So how's everyone feeling about C1/M1 tomorrow?

Posted from TSR Mobile

Reply 136

L'Evil Fish

OP

18

Original post by MathsNerd1

My lord this thread is on fire today! So how's everyone feeling about C1/M1 tomorrow?

Posted from TSR Mobile

So I set the thread on fiiiire, we can learn maths faaaster, than the.... Cant think of a woooord...

Either, way, I feel ready :colone:

come on C2 :woo:

wish C2 and HY1 were swapped... The dates

Reply 137

Zaphod77

1

Original post by MathsNerd1

My lord this thread is on fire today! So how's everyone feeling about C1/M1 tomorrow?

Posted from TSR Mobile

I'm doing M1, and I'm somewhat nervous... I keep doing such stupid mistakes :frown:

Reply 138

username937760

16

Original post by MathsNerd1

My lord this thread is on fire today! So how's everyone feeling about C1/M1 tomorrow?

Posted from TSR Mobile

Feeling pretty good about them. :colone:

Reply 139

username607202

17

Original post by MathsNerd1

My lord this thread is on fire today! So how's everyone feeling about C1/M1 tomorrow?

Posted from TSR Mobile

I'm going to hopefully secure 90+ ums tomorrow for C1. I am ready to make that exam my bitch. :smile:

Mega A Level Maths Thread MK II

Related discussions

Latest

Trending

Trending

Articles for you