Gym Locker

Julia was at the gym in the change room and there was an old lady who was having trouble with the combination of her lock on her locker.  So Julia offered to help her.  The lady told her the combination and Julia tried it and opened the lock and the locker for her.  She was very happy and thanked Julia.  Then old lady looked in her locker and noticed that it wasn't her stuff.  She told Julia that she must have the wrong locker.  So Julia found another locker with the same type of lock on it and opened it with the same combination and this time it was her locker.  She wondered which was stranger the old lady who didn't know which locker was hers or the lock company who made two locks with the same combination.