Permutations (1 Viewer)

[maths > english]

In how many ways can 5 men and 5 women be arranged in a circle so that the men are separated and 2 particular women are not next to a particular man?

 

[wogboy]

Have a look at the diagram I attached. M means a man's position, W means a woman's position. Since all the men have to separated, it must go man-woman-man ...

Those little numbers next to the M's and W's are the number of possible people that can sit at that position. The man who is circled in red is the man who the two particular women can't be positioned next to.

You'll notice that on one side of the circled man, there are 3 possible women that can sit there while on the other side there are 2 possible women. You can also work out the number of possible people for the other positions.

Multiply all the numbers together and you get 864.

 

[elizabethy]

i always hated doing permutations questions!! glad , i never have 2 do it again!!!

 

[freaking_out]

Originally posted by elizabethy
i always hated doing permutations questions!! glad , i never have 2 do it again!!!

well u might b asked to do it again at uni. if ur doing subjects like statistics.

 

[KeypadSDM]

Originally posted by freaking_out
well u might b asked to do it again at uni. if ur doing subjects like statistics.

Aww CRAP.

So glad they didn't ask this in the HSC.

 

[freaking_out]

Originally posted by KeypadSDM
....So glad they didn't ask this in the HSC.

yeah, tru true!

 

[elizabethy]

Originally posted by freaking_out
well u might b asked to do it again at uni. if ur doing subjects like statistics.