Relation between linear speed $\"\"$ of an object and angular speed $\"\"$ of the object is $\"\"$ , where $\"\"$ is the radius of the circular motion and $\"\"$ is measured in radians per unit time.

Radius of a circular paddle wheel is $\"\"$ .

Convert units from feets to miles :

$\"\"$

$\"\"$ .

Number of revolutions $\"\"$ .

$\"\"$

Convert minutes into hours :

$\"\"$

$\"\"$ .

Rotating speed of wheel means angular speed.

$\"\"$

$\"\"$ .

Consider $\"\"$ .

Substitute he values of $\"\"$ and $\"\"$ mile/hour in above formula.

$\"\"$

Thus, the speed of current is 2.86 mile/hour.

The speed of current is 2.86 mile/hour.