Economic systems include traditional, command, market, and mixed, each characterized by different methods of resource allocation and control. Traditional economies rely on customs, command economies are controlled by the government, market economies are driven by supply and demand, and mixed economies combine elements of both. Recognizing these distinctions helps in understanding global economic practices. ;
Approximately 2.81 \times 10^{21} electrons flow through an electric device delivering a current of 15.0 A for 30 s . This is calculated using the relationships between current, charge, and time. The total charge delivered during this time, divided by the charge of a single electron, gives the total number of electrons that flow.
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