Locker Puzzle
   

   

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The Locker Puzzle

There are one thousand students at the George Washington High School.  Each student is assigned a locker, numbered 1 through 1000.  On the first day of school each year, the students participate in an unusual ritual: The students enter the school through one door, parade past the all the lockers, and then exit through another door.  While in the school, the first student reverses the door position of each locker -- if the door is open, he closes it, and if it is closed, he opens it.  The second student reverses the door position of every other locker, starting with locker number 2.   The third student reverses every third locker, starting with locker number 3, etc.  After all 1000 students have completed this ritual, which lockers will be left open?

Answer

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