As firefighters, Doug, Kai, and Eli have been putting out a lot of fires over the week. Doug has put out 20 fires for the week and Kai has put out 3 times more than Doug. Meanwhile, Eli has put out half the number of fires Kai was able to. How many fires have they put out for the entire week?
Please reason step by step, and put your final answer within \boxed{}.
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