Answer

2.78 hours 🎯

Solution

The problem is like a clock problem in algebra, only with two "hands" with speeds close to each other. (The time it takes for Fang to be beside Vision is the same as the time it takes for Vision to be beside Fang.)

The circumference of the circular race track is approximately 9,999.69 meters. Fang and Vision are approximately 4999.85 meters away from each other.

Every second, Vision covers 2.5 meters and Fang covers 2 meters in the same direction, so there are 0.5 meters per second Vision is closer to Fang from behind. Half a meter per second is equivalent to 3,600 meters per hour. Therefore, by just dividing 4999.85 meters by 3,600 meters per hour, we get the exact time Vision will need to be beside Fang.

9,999.69 meters / (3600 meters per hour) = 2.7777 hours