Question

I need help with question 8 .

Answer 1

The bike is maintaining "constant velocity".  He's moving at 15 m/s when we see him for the first time, 15 m/s later that day, and 15 m/s next week.

The car starts from zero, and goes 4.0 m/s FASTER each second. After one second, it's going 4.0 m/s. After 2 seconds, it's going 8 m/s. And after 3 seconds, it's going 12 m/s.  

This is the point at which the question wants us to compare them ... 3 seconds.  The bike is moving at 15 m/s and the car has sped up to 12 m/s. The bike is moving faster than the car.

If we hung around and kept watching for another second, the car would then be moving at 16 m/s, and would be moving faster than the bike.  But we lost interest after answering the question, and we left at 3 seconds.