Question 403309
Draw a picture and you'll see that kids #5 through #11 will be in between #4 and #12 (note: we at least know that there are 12 kids). So there are 11-5+1 = 7 kids that are between #4 and #12



So because of symmetry, this means that there must be 7 kids in between kid #12 and kid #4 (say the circle starts at kid #4, so it wraps around back to the kid #4). So add 7 to 12 to get 19. Now realize that there are kids #1, #2, and #3 (which are before #4), so we have to subtract 3 from 19 to get 16 (since we've over counted). So there are 16 kids in the circle.