Maths Paper 6 2004 Help Please!!

[gogoace]

As title states!!!

Paper 06 2004 OCt/NOV --

Please help in Question 1. ii)

its a perm/comb question , i do countless past exams papers but i always get so confused in doing them

Any help would be appreciated on how to do this..

9709/06/ON/04

 

[soumayya]

(i) no. of different arrangements using all nine letters = 9! / (2!x2!) = 90720
as there are 9 letters, u have to do 9!...but u should divide by (2!x2!) since there are 2 A and 2 N

(ii) CVCVCVCVC
no. of ways of arranging the consonants = 5! / 2!=60 (u hve to divide by 2! bcz there are 2 similar consonants N)
no. of ways of arranging the vowels = 4! / 2! =12 (u hve to divide by 2! bcz there are 2 vowels A)
no. of arrangements containing alternate C and V = 60 x 12 = 720

Hpe zis hlps...

 

[gogoace]

Thank you for that!

Except the question asked it has to be in order CVCVCVCVC and although your answer is correct, wouldnt your way mean any arrangements in the total 9 letters ? like CVVCVCCCV something like that could still result in 720?

 

[soumayya]

Thank you for that!

Except the question asked it has to be in order CVCVCVCVC and although your answer is correct, wouldnt your way mean any arrangements in the total 9 letters ? like CVVCVCCCV something like that could still result in 720?

didn't quite get u...