A factory produces two types of gadgets: Gizmos and Widgets. Each Gizmo requires 3 hours to assemble, and each Widget requires twice as much time as a Gizmo to assemble. If the factory assembles 5 Gizmos and 4 Widgets in a day, how many total hours are spent on assembly? Let's think step by step and output the final answer within \boxed{}.
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