The train, moving uniformly accelerated along the straight section of the railway, covered the distance S = 400m

The train, moving uniformly accelerated along the straight section of the railway, covered the distance S = 400m for the time interval t = 20s. If the modulus of the train speed at the beginning of the track Uo = 10m / s, then the modulus of its speed U at the end of the track is?

For uniformly accelerated motion of bodies, there is a formula s (t) = v0 * t + (a * t ^ 2) / 2, where s is the distance traveled, v0 is the initial speed of motion, t is the time of motion, and a is the acceleration. We use this formula to find the acceleration.
a = 2 * (s – v0 * t) / t ^ 2 = 2 * (400 m – 10 m / s * 20 s) / (20 s) ^ 2 = 200 m / 400 s ^ 2 = 0.5 m / s ^ 2.
Next, we will use the formula v = v0 + a * t, where v is the final speed of movement.
Thus, v = 10 m / s + 0.5 m / s ^ 2 * 20 s = 20 m / s.
Answer: v = 20 m / s.