Moving uniformly accelerated, the material point passes

Moving uniformly accelerated, the material point passes the paths of 20 m and 30 m in two successive time intervals. The value of each time interval is 4 s. Determine the initial speed of the point.
10574. A detailed solution with a brief note of the conditions, formulas and laws used in the solution, the derivation of the calculation formula and the answer.
If you have any questions about the solution, write. I try to help.