Final answer:
The total distance Sean biked over three days cannot be calculated with the provided information, as there are no specific distances given for each day.
Step-by-step explanation:
The total distance Sean biked over three days cannot be determined from the information provided in the reference texts. The references provided discuss the concept of displacement and distance traveled by a cyclist, average speed, and a velocity example with another cyclist. However, there is no specific information about Sean's biking distances on Friday, Saturday, and Sunday to calculate the total.