Final answer:
The slope of the demand curve is 40.
Step-by-step explanation:
The demand curve for pizza can be determined by calculating the slope using the formula:
Slope = (Change in Quantity Demanded) / (Change in Price)
Using the given information, we can calculate the change in quantity demanded and change in price:
Change in Quantity Demanded = 300 - 100 = 200 slices
Change in Price = $5 - $10 = -$5
Therefore, the slope of the demand curve is: -200 / -5 = 40
So, the correct answer is option (b) 40.