Two ice skaters started on opposite ends of a 200-foot-long rink and then skated toward each
 other at constant speeds. The faster skater traveled 7 feet for every 6 feet the slower skater
 traveled. If x represents the number of feet the slower skater had traveled at the moment the
 skaters passed each other, which proportion can be used to find x?
 6
 200
 6
 200
 6
 (6+7)
 200
 7
 (6+7)
 200