Two cars travel from point A to point B, a distance of 200km. Car X travels at an average speed of 60km/h with a tyre radius of 20cm, while Car Y travels at an average speed of 50km/h with a tyre radius of 25cm. Assuming all other conditions are identical, which car arrives at point B first? (a) car X (b) car Y (c) both arrive at the same time (d) cannot be determined