To determine how many more chocolate bars Dennis needs to sell to win a prize, we can first find out how much more he needs to sell beyond the $175 required for the prize.
- Current sales: $40
- Amount needed for the prize: $175
Let's calculate how much more he needs to sell:
\[ 175 - 40 = 135 \]
Now, since each chocolate bar sells for $2.50, we need to calculate how many bars he needs to sell to make up that $135.
Let \( x \) be the number of additional chocolate bars he needs to sell:
\[ 2.50x = 135 \]
Now, solve for \( x \):
\[ x = \frac{135}{2.50} \] \[ x = 54 \]
Therefore, Dennis needs to sell 54 more chocolate bars to reach the total of $175 and win the prize.