Miguel is making an obstacle course for field day. at the end every sixth of the course, there is a tire. at the end of every third of the course ,there is a cone. at the end of half of the course, there is a hurdle. at which locations of the course will people need to go through more than one obstacle

People will need to go through more than one obstacle at three places in the course:  The 1/3 mark, the 1/2 mark, and the 2/3 mark.

The tires are at these spots
--\--\--\--\--\--\

The cones are at these spots
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And the hurdles are here:
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When you combine these:
--\--\\--\\--\\--\--\\\

You get two marks at the 1/3, 1/2, 2/3, and Final spots (Final can be 1, 2/2, 3/3, or 6/6.)