Since nobody knows the correct answer, it must be several thousand miles per hour.
1.2 mph
I would call it current speed, not average speed.
velocity
The average speed of the Gulf Stream current in the Atlantic Ocean is about 4 miles per hour.
It depends on the time of year and where in Africa.
The speed of the Mississippi River varies depending on the location at which it is measured. At the headwaters, the flow is about 1.2 miles per hour. In New Orleans, far downriver from the headwaters, the river flows at about 3 miles per hour. For comparison, most people walk at about 3 to 3.5 miles per hour.
To set up the equation for finding the current of a river, you typically consider the speed of a boat relative to the water and the speed of the boat relative to the ground. Let ( v_b ) be the speed of the boat in still water, ( v_r ) be the speed of the river current, and ( v_g ) be the speed of the boat relative to the ground. The equation can be expressed as ( v_g = v_b + v_r ) when the boat is moving downstream and ( v_g = v_b - v_r ) when moving upstream. By measuring the ground speed in both directions, you can solve for ( v_r ).
The velocity of the boat relative to the shore is the vector sum of its velocity relative to the river and the velocity of the river current. In this case, it would be 4 km/h (boat's speed) + 5 km/h (current's speed), which equals 9 km/h.
A car's speedometer typically shows the instantaneous speed, which represents the current speed of the vehicle at any given moment. It does not show average speed or velocity.
The speed of the flow changes depending on season, rainfall, width, depth, gradient and where in the river you measure it. However the total outflow averages approximately 209,000 m3/s (7,381,000 cu ft/s).
This will depend not only upon the strength of the current (in Amperes), but also on the wire's cross-section. In any case, in a typical current, the electrons have an average speed of a tiny fraction of a milliter per second.
The Gulf Stream current flows at an average speed of about 4 miles per hour.