def calculate_final_drive_speeds_in(final_drive_speeds_out,
    final_drive_ratio_vector):
    """
    Calculates final drive speed [RPM].

    :param final_drive_speeds_out:
        Rotating speed of the wheel [RPM].
    :type final_drive_speeds_out: numpy.array | float

    :param final_drive_ratio_vector:
        Final drive ratio vector [-].
    :type final_drive_ratio_vector: numpy.array | float

    :return:
        Final drive speed in [RPM].
    :rtype: numpy.array | float
    """
    return final_drive_speeds_out * final_drive_ratio_vector
