A vector quantity is : A deer running 15 meters per second due west

True.

Explanation:

Velocity can be defined as the rate of change in displacement (distance) with time. Velocity is a vector quantity and as such it has both magnitude and direction.

Mathematically, velocity is given by the equation;

Simply stated, a vector quantity has both magnitude and direction.

Thus, a vector quantity is: A deer running 15 meters per second due west.