the mean is the average of the 6 numbers, in order for the total average to increase by 3 points, that is like saying each of the 6 values increased by 3 points each, 3 × 6 = 18, now each one would not actually have to increase by 3 each, as long as the total increase of adding all 6 numbers together was 18 points higher, then the average would be 3 points higher
