So we want to know what is the current flowing trough the electric circuit if the voltage U=60V and the resistance R=12 ohms. So to know the answer we need to know Ohms law that states I=U/R. This measn that the current in the circle is the voltage U divided by the resistance R. So now we plug in the numbers and get: I=60V/12ohms=5 A. So the current is I=5A.
