The cyclist moves along a straight section of the highway. the figure shows a graph of the dependence

The cyclist moves along a straight section of the highway. the figure shows a graph of the dependence of a cyclist’s path on time. what was the speed of the cyclist 4 seconds after the start of the movement.

Let’s take a time of 30 s and a distance of 150 m.
The speed here is 150/30 = 5 m / s.
The section from 20 s to 30 s is clearly 10 m / s, since the speed there is the highest possible option. Section from 0 s to 20 s – speed 2.5 m / s.
Then it turns out: 1.25 m / s.
Answer: 1.25 m / s.