Figure 7 shows how the demand for electricity varied with the time of day.

What was the difference between the maximum demand and minimum demand for electricity during this day?

To find the difference, we must first read the maximum and minimum values from the y-axis of the graph. - **Maximum Demand:** The highest peak of the graph occurs at around 09:00. Reading across to the y-axis, this value is 38,000 MW. (Each small grid line on the y-axis represents 1,000 MW). - **Minimum Demand:** The lowest point of the graph occurs at around 04:00. Reading across to the y-axis, this value is 25,000 MW. - **Difference:** Difference = Maximum demand - Minimum demand Difference = 38,000 MW - 25,000 MW Difference = 13,000 MW