Answer:
6
Step-by-step explanation:
We have 6 seats in a row:
1 2 3 4 5 6
We have 3 couples to fit into 3 slots:
Slot 1: First 2 seats
Slot 2: 2 middle seats
Slot 3: Last 2 seats
(Note: they can't sit in seats 2 and 3, with another couple in 4 and 5 - as the last couple would need to be separated in seats 1 and 6)
The first slot can have any of the 3 couples.
The second slot can have any of the 2 remaining couples.
The third slot can only have the 1 remaining couple.
3 options (slot 1), each of those having 2 options (slot 2), with each of those only having 1 option (slot 3).
Total number of options is thus,
3 * 2 * 1 = 6
