Probability Help (1 Viewer)

[Lamak]

Can some1 plz help me with this prabability q

a queue has 4 boys and 4 girls standing in line. find how many different arrangements of the line are possible if the boys and girls alternate...

 

[rama_v]

4 B 4G
BGBGBGBG

4!x4!x3!x3!x2!x2!x1!x1! x2 because u can start with a girl too.

is that right? Its been a while since ive done permutations lol.

 

[Slidey]

8 people in total.
x=boy, y=girl
x y x y x y x y
OR
y x y x y x y x
In each case, 4!*4!
2 cases, though, so 2*4!*4!
=2^7.3^2=128*9=900+270-18=1152

 

[Lamak]

nah the answer is 1152, thanx neways

 

[Slidey]

4 B 4G
BGBGBGBG

4!x4!x3!x3!x2!x2!x1!x1! x2 because u can start with a girl too.

is that right? Its been a while since ive done permutations lol.

Close...

Should read:
4x4x3x3x2x2x1x1 x2 because you can start with a girl too.

 

[Lamak]

thanx slide =)

 

[rama_v]

lol yeah Im so stupid Thanks slide

 

[Slidey]

Nah you're not. You were on the right track. I know what it's like to try and answer questions for a topic you did many months ago and haven't revised since.

 

[Pace_T]

..or because its a shitty ass topic, lol