According to the classical law of addition of velocities, the speed of a body relative to a stationary frame of reference is equal to the sum of the speed of a body in a moving frame of reference and the speed of a moving frame of reference relative to a stationary one. However, it has been experimentally proven that the speed of light does not depend on the speed of the frame of reference, but is a constant value, i.e. invariant.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.