To find Buck's new average after scoring 118 in his next game, we first need to calculate his total score from the first 5 games.
Given that his average over 5 games was 100, we can calculate his total score for those games:
\[ \text{Total score for 5 games} = \text{Average} \times \text{Number of games} = 100 \times 5 = 500. \]
Now, we add the score from the next game:
\[ \text{Total score after 6 games} = 500 + 118 = 618. \]
Now, we can calculate the new average over the 6 games:
\[ \text{New average} = \frac{\text{Total score after 6 games}}{\text{Number of games}} = \frac{618}{6} = 103. \]
Therefore, Buck's new average after scoring 118 in the next game is 103.