Hi SDW2,
There's an easy, visual way for you to see exactly what this phrase refers to - and all you will need is a pen and a piece of paper:
1) Draw a circle.
2) Write the numbers 1 - 10 around the edge off the circle. These numbers represent the 10 chairs.
3) Rotate the paper.
Notice how any of the ten numbers can be at the 'top' of the circle, but the relative positions of the 10 numbers is always the SAME (for example, #2 is always between #1 and #3). These are NOT 10 different arrangements; it's 1 arrangement (because the table is a circle). This is why you have to adjust your calculation when dealing with these types of questions.
GMAT assassins aren't born, they're made,
Rich