Final answer:
The instantaneous speed of an object with an instantaneous velocity of 20 m/s to the east is 20 m/s, as instantaneous speed is the magnitude of the velocity vector without considering direction.
Step-by-step explanation:
If an object has an instantaneous velocity of 20 m/s to the east, then its instantaneous speed is simply the magnitude of the velocity vector, which in this case is 20 m/s. Instantaneous speed does not take direction into account, only the magnitude of the velocity. Therefore, even when the net displacement is 0 m and the total distance is 40 m, if the object has an instantaneous velocity of 20 m/s at any moment, its instantaneous speed at that moment is 20 m/s regardless of the previous or following motion.