Num

[mikalaisin]

There are 10 people, 5 married couples. We need to sit them in a row, where each married person sits next to his/her spouse. How many arrangements are possible?

1. 45
2. 120
3. 240
4. 3628800
5. Other


My Solution (highlight below):
let's assume that 1 married couple is 1 person, so number of arrangements to sit those people is 5!, however each pair has possibility to be sitted in 2 ways. For example we have couple 1 and 2, so there are 2 possibilities 12 and 21. Thus we need 5!*2^5=3840 I can't find anywhere right solution for this problem, please help me to understand whether my solution is correct.

[RonPurewal]

per the forum rules, we need a citation of the original source. thanks.

[RonPurewal]

also, perhaps you're forgetting that 'Other' is given as an answer choice. (: