Final answer:
The speed of the person riding their bike is calculated using the formula speed = distance/time, resulting in a speed of 2.5 m/s or option (a).
Step-by-step explanation:
The question being asked is related to determining the speed of a person riding their bike. To calculate the speed, we should use the formula speed = distance/time. In this case, the rider travels 50 meters in 20 seconds, so:
Speed = 50 meters / 20 seconds = 2.5 meters per second (m/s).
Therefore, the rider is traveling at a speed of 2.5 m/s, which corresponds to option (a).