9709/62 stats . 5 nov.2012

[Nishii]

i found it's is not very hard. ON2010 is harder than yesterday's!
But I'm not sure though for the permutation combination part ii.

the grade threshold for nov 10 p62 is 33, probably ours will be approximately the same!
and permutation part (ii) is definitely wrong for me.. i did 12P8 - [(12C2 x 11 x 2!) + (10C6 x 6!)]..
i think it should have been 12P8 - [(11 x 2!) + (10C6 x 6!)]..

 

[hanyigcse]

the grade threshold for nov 10 p62 is 33, probably ours will be approximately the same!
and permutation part (ii) is definitely wrong for me.. i did 12P8 - [(12C2 x 11 x 2!) + (10C6 x 6!)]..
i think it should have been 12P8 - [(11 x 2!) + (10C6 x 6!)]..

i did this question as the following ,i took the two persons as one person and two seats as a one then i made 12p8-(11p7 x 2)

 

[hanyigcse]

anyone to confirm the answer?

 

[Khalifa]

I did it like this- part a) no restrictions-12P8 or 12!/4!- consider blank seats as repitition= 19958400
b) if we consider the 2 to be together, we form 11 blocks. - 11! Ways. However 4 blank seats so count that as repition
So 11!/4!. Now multiply by 2 as 2 it can be done in two ways so2*11!/4!= 3326400
Now subtract from part a to get 1663200
c) all 8 people together- consider them to be 0ne block. Within can be arranged in 8! Ways. Along with 4 other blocks can be arranged in 5! ways. However 4 repititions so 8!*5!/4!= 8!*5=201600

Is this correct?

 

[athaan]

I did it like this- part a) no restrictions-12P8 or 12!/4!- consider blank seats as repitition= 19958400
b) if we consider the 2 to be together, we form 11 blocks. - 11! Ways. However 4 blank seats so count that as repition
So 11!/4!. Now multiply by 2 as 2 it can be done in two ways so2*11!/4!= 3326400
Now subtract from part a to get 1663200
c) all 8 people together- consider them to be 0ne block. Within can be arranged in 8! Ways. Along with 4 other blocks can be arranged in 5! ways. However 4 repititions so 8!*5!/4!= 8!*5=201600

Is this correct?

THIS. I DID THE SAME THING. I hope it's right.

 

[Souhayl]

The chemistry paper 2 was damn easy ,can anyone tell me the grade is got(1,2,3,4,5......) if got 52 out of 60?