1. The problem asks how revenue changes when price changes from $10.00 to $9.75 and from $10.50 to $11.00. 2. Revenue is calculated as $$\text{Revenue} = \text{Price} \times \text{Quantity}$$. 3. Without knowing how quantity demanded changes with price, we cannot determine the exact effect on revenue. 4. If quantity demanded increases enough when price decreases, revenue can increase; if not, revenue decreases. 5. Similarly, if quantity demanded decreases enough when price increases, revenue decreases; if not, revenue increases. 6. Since the problem does not provide demand elasticity or quantity data, the correct answer for both questions is (d) Can't tell.