In a science class, students are comparing the weights of different objects. They have three sets of weights: Set A, Set B, and Set C. Set A has three objects weighing 250 grams each, Set B has four objects weighing 200 grams each, and Set C has five objects weighing 150 grams each. What is the average weight of all objects combined in kilograms? Let's think step by step and output the final answer within \boxed{}.
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