18 people in a circle. 18th person across from 7th person. How many people in the circle

Question

18 people in a circle. 18th person across from 7th person. How many people in the circle

Answer 1

there are ten people between 7th and 18th.  If they are cross from each other, then, there must be ten people between them on the other side too.  There are six people to the left of 7, then there must be 4 people to the right of 18.

 

So, 22 people in a circle.

Answer 2

Did you draw a diagram?

7 and 18 are ends of a diameter.

11 people are on either side

Now can you answer?