1. Total Distance and Laps Covered by X and Y: The race distance is 3 km, or 3000 meters. Since the track length is 300 meters, X needs to complete $3000/300 =10$ laps to finish the race.

2. Laps Completed by X and Y: Since their speeds are in a 3:2 ratio, by the time X completes 10 laps (covering 3000 meters), Y will cover only $(\frac{2}{3}) \times 10 = 6.66$ laps. Thus, when X completes the race (10 laps), Y will be only partway through the 7th lap.

3. Frequency of Passing: X and Y will meet every time X gains a full lap on Y. Since X’s speed is 1.5 times Y’s speed (3:2 ratio), X will pass Y once for every 2 laps X completes. Therefore, by the time X completes his 10 laps, he will have passed Y 3 times.

Thus, throughout the race, X will pass Y exactly 3 times, not counting their start together.